Factors Influencing Environmentally Friendly Air Travel: A Systematic, Mixed-Method Review

2.1 Research Approach

This work aims to comprehensively review and structure the internal and external factors that affect the environmental awareness and behaviour change of air passengers. Internal factors are defined as factors based on humans’ intrinsic motivation. External factors influence humans from the outside. Both types of factors have the potential to affect human awareness. For our research process, we applied a mixed-method approach. First, we performed an SLR to identify those factors affecting passengers’ environmental awareness that have already been discussed in the scientific community. Second, we conducted semi-structured expert interviews (Bogner et al., 2014) to validate the external factors and find initial solutions to close or reduce the awareness–behaviour gap. Interviews with experts from the industry are an established research method to complement findings (Bogner et al., 2014). The interviews were necessary because the literature on external factors, such as policy and information, is scarce, and the method seemed to be suitable in this research context to complement the literature review. Comparing the findings of the SLR and expert interviews, we see that the SLR findings are partially confirmed by the experts, especially regarding the impacts of the known external factors. Other opinions from the experts are included to extend the theoretical model developed based on the SLR. Finally, we propose a final conceptual model based on the results of the SLR and expert interviews. Figure 1 illustrates the methodology framework.

Figure 1

Overview of the research approach.

2.2 Systematic Literature Review

We entered our search terms into the Scopus and Google Scholar databases and cross-checked them in the OpenAlex catalogue (Priem et al., 2022), including environmental attitude, environmental behaviour, environmental awareness, environmental concern, pro-environmental attitude, pro-environmental behaviour, attitude–behaviour gap, aviation, air passenger, air travel, and air transportation. The search included title, abstract, and keywords. Based on the search, we identified 2,612 studies published between 2002 and early 2024. After excluding 2,052 studies that were not relevant to air transport, 560 studies remained. In the next round, we identified 256 studies focused on investigating air passengers’ environmental attitudes and behaviours. Driven by our goal to identify the most relevant factors that could influence air passengers’ environmental attitudes and behaviours, in the end, we selected the 111 most relevant studies that reveal the factors and their direct and indirect impacts on air travellers’ pro-environmental attitudes and pro-environmental behaviour. Studies that reveal the relationship between attitudes and behaviours, for instance, the attitude–behaviour gap, were also selected. The remaining 145 studies were not focusing on studying the impacts of individual factors or the attitude–behaviour relationship and were therefore out of the scope of our study. Among these 111 most relevant studies, 105 investigate passengers’ attitudes and behaviours regarding general air travel, while the remaining six studies reveal attitudes and behaviours toward adopting novel aircraft, such as drones and electric aircraft. The studies were published as journal articles, PhD dissertations, and book chapters. Figure 2 summarizes the steps involved in the SLR. The results of the SLR are in Section 3, as well as the appendices.

Figure 2

A flow diagram for the selection of relevant studies.

2.3 Semi-Structured Interviews

For the expert interviews, we identified and approached suitable sustainability experts via the professional social media platform LinkedIn, company websites, and our own professional networks. We selected experts from Europe to keep the geographical scope. Various stakeholders belong to the air transport system. Hence, we interviewed a diverse panel to include many points of view. To gain a practical view on the topic, we approached industry experts. Further, we approached academic experts who have also published studies discussed in this article. Out of 81 interview requests, 14 experts agreed to participate in the interviews, leading to an overall response rate of 17.3%. All interviewees were anonymized in this study. Due to geographical barriers, the interviews were conducted using online communication platforms such as Skype, Zoom, Google Meet, and Microsoft Teams. The interviews were conducted between mid-2019 and spring 2020, providing a pre-COVID-19 view. As part of the initial interview request, all experts were informed about the background of the study and provided with contact details about the interviewer and all institute information. Informed consent regarding the use of their interview data was obtained from all individuals prior to the study. All interviews were conducted voluntarily. The interview design was semi-structured (Bryman, 2016), following three sub-sections with a list of leading questions (Qs). All interviews were recorded and transcribed and lasted around 30 min. The interviews were structured as follows:

1. After an introduction about the interview purpose and aim of this research, the first section started with two open questions, asking for personal and organizational views:

   • Q1: How would you describe the situation of environmental awareness of European air passengers?

   • Q2: What channels and methods are most effective for activating European air travellers’ ecological action?

2. The second section began with providing the first interim results from the prior literature review on external factors, asking about their experts’ reflections and professional feedback. By giving these interim results, experts were triggered to rethink their points of view and evaluate the first model draft (e.g. whether they agree or disagree and to determine the reason behind each answer):

   • Q3: Which one do you think is the most effective channel (from government, from customers’ intrinsic intention, or social media parties) and why?

   • Q4: Should all the channels mentioned above target the customers with pro-environmental awareness first or target the entire society?

1. The third section was open (meaning in this context that no specific answers or areas to cover were expected) and adapted depending on the conversation during the interview. After that, the interview was closed.

   • Additional related information from other experts was provided (anonymously) in this section, potentially to trigger more ideas and opinions across all the organizations on the interview list.

   • The interview closed with a review and summary of the experts’ opinions.

2.4 Interview Sample

Seven types of organizations were approached and interviewed: (1) airlines, (2) non-governmental organizations (NGOs), (3) academic organizations, (4) aerospace companies, (5) private transport companies, (6) airports, and (7) other international aviation organizations. Most experts were located professionally in Western and Northern Europe. Out of the total interviewee sample of 14 experts, 29% are female (N = 4) and 71% are male (N = 10), each with different seniority levels (Table 1 for an overview). The results of the interviews will be presented in Section 3.

3.1 Findings from the Literature Review

While 111 studies were initially identified as relevant to the broader topic, only 71 of them explicitly investigated the impact of specific factors on environmental attitudes/awareness (terms used interchangeably in this article) and/or air travel behaviours. The remaining studies were excluded from the analysis because they either lacked empirical examination of such factors or focused on unrelated aspects. Among the 71 studies analysing the impacts of various factors, most collected empirical data using survey-based approaches. The sample sizes of these studies vary between N = 10 to N = 3,998. Qualitative studies based on interviews, focus groups, and lab experiments tend to have smaller samples (maximum 78 in this context), whereas quantitative analyses based on surveys have larger sample sizes (at least 128 in this context). Figure 3 shows that the majority of the studies were published after 2012. Some studies, such as those by Cocolas et al. (2020), Garrard (2013), Markham et al. (2018), Moira and Parthenis (2022), and Sobieralski and Hubbard (2020), were excluded due to undefined sample sizes. Additionally, the study by Mattioli et al. (2023) was based on secondary data analysis. It can also be seen in the scatter plot that sample sizes have increased slightly in recent years, likely due to the proliferation of the Internet, the expansion of data collection tools, and possibly the growing relevance of the topic. The primary study areas included the United Kingdom (UK), Australia, and the United States of America (USA), as shown in Figure 4. Studies like Cocolas et al. (2020) and Garrard (2013) did not specify the study areas.

Figure 3

Sample size of survey-based studies (66 studies).

Figure 4

Amount of published studies per study area (68 studies).

Among all 71 studies investigating the relevant factors, the majority (75%) collected empirical data through surveys or secondary sources. Quantitative statistical methods were commonly applied to analyse this data. Main data analysis methods include path analysis, structural equation modelling (SEM), regression analysis, and discrete choice modelling. Following the quantitative data collection and analysis methods, 15% of the studies conducted interviews, focus group studies, or combined surveys with interview studies. Qualitative analysis approaches, such as thematic analysis and comparative analysis, were the predominant methods employed for the qualitative data. Figures 5 and 6 present an overview of the methods applied for data collection and analysis in all 71 studies.

Figure 5

Applied data collection methods (71 studies).

Figure 6

Applied data analysis methods (71 studies).

In general, our study finds three main aspects that are relevant to air passengers’ environmental attitudes, environmental awareness, and air travel behaviour. These aspects include social-demographic characteristics such as age and income, internal factors that influence behaviour from within the individual, such as knowledge and values, as well as external factors that originate from an individual’s environment and shape behaviour from outside the individual, such as policy intervention and social factors. These factors can directly impact environmental attitude or awareness and air travel behaviours, or they can indirectly drive behaviour changes by affecting attitude and awareness. Figure 7 displays these factors in clusters, differentiating those that have impacts on the environmental attitude, air travel behaviour, or both. For instance, knowledge about climate change can directly affect individuals’ environmental attitudes, thereby influencing their travel behaviours. In other cases, external factors might initially affect individuals’ internal factors or particular sociodemographic groups, subsequently influencing their environmental attitude, awareness, and behaviour. For example, communication and policy strategies can be tailored to address the specific behaviours and circumstances of different demographic groups, taking into account their specific attitudes and behaviours. Based on the SLR, we focused on a few frequently mentioned behaviours and analysed how the factors mentioned above are related to these behaviours. These behaviours include reducing flying, considering flight eco-efficiency when booking, WTP more for carbon offsets, preference for air travel, choice of eco-friendly airlines, flight shame, support of airlines’ environmental policies, and intention to adopt novel aircraft technologies. Additionally, we draw conclusions about how general air travel demand is affected by the relevant factors.

Figure 7

Summary of factors identified through the SLR.

3.2 Findings from Interviews

Turning from our systematic literature review to our research, we will address the interviews first. Our expert interviews confirm some of the external factors explored above. Overall, we identify three main driving forces: governments, airlines, and social movement groups. The interview findings below are divided into three sections, presenting viewpoints representing these three groups.

From the governmental viewpoint, the experts suggest that governments should invest more in Research and Development (R&D) in sustainability. Governments should regulate the energy label with CO₂ emissions on flight tickets. It is an essential step to educate the public about the scale of the negative impact of greenhouse gas emissions by aviation (GHG-A). Besides, governments should tax fuel and reflect it on the ticket price, as multiple experts point out that most flight tickets are unreasonably low. That gives the public the wrong impression that there is only a minor environmental impact when travelling by air.

Governments should utilize the media as a communication tool for all the target audience types. Content should clarify how the tax the passenger pays in turn pays for fuel, creating more transparency for the passenger, providing GHG-A emission information, and encouraging the use of alternative transportation modes. Besides, the government should also regulate flight booking sites to display the GHG-A emission of each flight.

Furthermore, consistency is the key factor in minimizing the environmental attitude–behaviour gap. The government should consistently provide transparent information to the public, as many experts point out that human memory about the environmental impact is short. If the information is only provided periodically, the effectiveness of minimizing the attitude–behaviour gap is limited.

Last, information to educate the public is mentioned by almost 100% in response to Question 2 (What channels and methods are the most effective for activating European air travellers’ ecological action?). Interestingly, one of the experts mentions the importance of integrating the environment as a topic into the mandatory curriculum in the educational system. The positive impact of education can be significant over time. It is critical to educate children about nature and the importance of environmental consciousness from an early age. In the long run, the effectiveness of this approach is likely to be higher than attempting to re-educate adults, as the status quo has been established. Furthermore, the expert pointed out that children can often educate their parents about the topic more effectively than any external educational measure.

The importance of airlines’ efforts in changing consumer behaviour is noted 100% of the time. However, experts from non-airline organizations are sceptical about the effectiveness of programs for offsetting emissions and whether they can change consumer behaviour, as offsetting has no direct relationship with reducing GHG-A emissions. Some experts even perceive offsetting as a “distraction” and “white lie,” misleading the public into believing they can compensate for their GHG-A footprint by paying a small fee, which is a delusion that the environmentally negative impact can be easily erased. Overall, offsetting schemes are not seen as an effective, long-term way to change consumer behaviour but merely to trigger awareness. Given the extensive literature on offsetting, its actual effect should be reconsidered.

In fact, according to the interviewees, airlines should rework the entire purchase journey of the flight ticket. Airlines should always provide information about each flight’s emissions. At the time of this research, in most cases, the data are provided within the confirmation email after the booking process. Presenting the information about emissions before finalizing the booking would give passengers at least the opportunity to reconsider the necessity of flying – especially domestic flights within Europe. After reading the information about GHG-A emissions, offsetting should be set as the default and opt-out option during the booking process to increase awareness.

Alongside offsetting, there are multiple approaches that airlines can adopt to raise environmental awareness and possibly change consumer behaviour. The media can be used as an intermediary to communicate with the public. Adopting media as a channel is mentioned by 43% of the experts during the interview. First, accurate information should be provided in the in-flight magazine. Several experts indicate that there is no standard calculation of GHG-A emissions, and airlines typically underestimate the GHG-A of each flight intentionally. Therefore, providing accurate details on GHG-A emissions can be a practical approach to minimizing the attitude–behaviour gap. More than half of the experts interviewed argue that the unrealistically low-cost flight deals should be banned. Ticket price competition among airlines has been on-going for decades. Most experts point out that airline operators use price as a strategy to create a competitive advantage over others and to indirectly convey the wrong message to the public that environmentally harmful externalities, such as flight emissions, are free. Banning unrealistic deals and rethinking the competitive strategy to include environmental concerns could be a viable solution. Business operations should be combined with taking care of social responsibilities by sending direct and indirect messages about the environmental impact of air travel to the public. Doing so can benefit the reputation of airline operators themselves and gain support from the public.

All in all, information is the key to triggering environmental behaviour change among air travellers. Airlines should ensure that the information about GHG-A is conveyed correctly and consistently, as our interviews identify misinformation and a lack of education as the primary causes of the environmental attitude–behaviour gap. It is essential to keep in mind that information about GHG-A emissions should be clear and precise.

Interviewees mention social movements as driving forces in more than half of the interviews. Experts from different organizations mention Greta Thunberg, Extinction Rebellion, and the flygskam (flight shaming) phenomenon, which have gained momentum in recent years. Social activities indeed have the advantage of triggering environmentally friendly behaviour change. As the literature reviews show, governmental intervention is the most effective way to activate environmental behaviour change and mitigate the attitude–behaviour gap. However, several experts mention that social movements have a more significant impact on society and a better chance of changing air travellers’ behaviour. These public figures actively disseminate relevant information about GHG emissions, potentially influencing the public. The values, concerns, and movements aimed at fighting climate change are effectively spread through media channels. Notably, the power of peer-to-peer communication is significant on all kinds of social media platforms. Initially, the target audiences of some social movements are primarily younger generations. Recently, however, raising environmental awareness and changing consumer behaviour influenced by these environmental social movements have been observed across all age groups within Europe. They convey a powerful message addressing the urgency of solving environmental issues and climate change, capturing the public’s attention along with that of international organisations and governments. Experts point out that these environmental social movements are one of the forces driving the improvement of environmental awareness and behaviour change over the past few years. All generations are paying more attention to climate change and are more conscious about travelling and their lifestyle.

Conversely, some experts express concerns about the environmental groups mentioned. Their basis of information might be biased because it is emotionally charged and sometimes only familiar with a partial context of the related topic. Although the role of social movements is debatable and contradictory, they still play a vital role in addressing the issue and influencing policies.

3.3 Formation of a Conceptual Model

Overall, the expert interviews confirm the findings from the SLR, particularly regarding the impacts of external measures on attitudes and behaviour change. These measures include fuel tax, educating the public, providing emissions information, and social movements. Complementary to the SLR results, the experts highlight governments, airlines, and social movement groups as three major parties driving these marketing and policy interventions. Besides economic measures and educating the public to improve environmental awareness, the government is expected to provide more transparent information about emissions, as do the airlines. Extending the findings from the SLR, the experts also point out the relevance of and issues with low air ticket prices, which convey the wrong message and lead to people’s underestimation of the environmental impacts of air travel.

Moreover, extensive studies consider passenger support of carbon offsetting to be an environmentally friendly action. Although the effectiveness of carbon offsetting is questioned by the experts during our interviews, evaluating that issue is outside the scope of this study. Finally, despite potential emotional bias, interviewees emphasise the importance of social movements, which aligns with the relevance of social norms revealed by the SLR. Based on insights from the SLR and expert interviews, a conceptual model is developed and shown in Figure 8. The model explicitly clarifies how various factors interact and influence traveller decisions and highlights the prevalent attitude–behaviour gap in aviation. The primary purpose of the model is to enhance clarity and mutual understanding among key stakeholders, including policymakers, airlines, social movement groups, NGOs, and passengers themselves. By explicitly identifying the relationships and responsibilities associated with each factor, this model provides a shared framework to guide collaborative efforts towards more effective interventions and targeted policy measures aimed at bridging the attitude–behaviour gap in aviation. The model depicts the main external and internal drivers of passengers’ environmental awareness, some of which might influence behaviour directly (e.g. monetary measures) or indirectly via increasing awareness (e.g. education). For instance, raising awareness with external strategies (e.g. marketing campaigns) is a topic of education and transparency, and passengers need more information to make an informed decision (e.g. via eco-labels, transparent information on emissions within the booking process). Strategies need to be targeted toward different segments according to the demographic characteristics or travel patterns (e.g. young passengers, business passengers) and relevant internal factors (e.g. norms, knowledge). Social media could be a mediator providing channels to influence passengers’ decisions.

Figure 8

Final conceptual model of factors influencing environmentally friendly air travel.

The model emphasises the gap between environmental awareness/attitudes and behaviour or behavioural intention, the latter often considered a proxy for actual behaviour (Ajzen, 1991). To narrow the attitude–behaviour gap, measures should be implemented to enhance awareness and simultaneously foster behavioural change. The proposed strategies include

• Government and policy Interventions: These include a range of measures from “soft” regulatory efforts like social marketing and public health campaigns to “hard” policy measures such as taxation, caps on emissions, and inclusion of aviation in emissions trading schemes. The necessity of government action to achieve radical emissions reductions is emphasised, suggesting a belief in the insufficiency of voluntary measures alone to induce significant behavioural change. (Eijgelaar, 2011; Gössling & Peeters, 2007; Higham et al., 2016; Mkono, 2020). Policies should not only aim to reduce overall emissions but also consider the varied ways individuals contribute to transport emissions. (Mattioli et al., 2023) To operationalize these goals, a phased approach could be implemented: in the short term, governments could launch national campaigns highlighting the climate impact of aviation, maintaining continuous visibility across television, digital media, and public spaces. In the medium term, mandatory eco-labelling of flight options displaying CO₂ emissions at the point of ticket purchase could enable more informed consumer choices. In the long term, for example, progressive ticket taxation based on travel distance and emissions class could be introduced.

• Improving the carbon offsetting framework: Measures proposed include enhancing the credibility and transparency of carbon offsetting schemes, integrating offset options more seamlessly into booking processes, and considering mandatory offsetting. The need for offsetting schemes to follow consistent standards for validation and verification is highlighted to build trust among consumers (Eijgelaar, 2011; Gössling et al., 2009). It requires collaboration between governments and regulatory bodies, airlines, and carbon offset providers. All offset projects offered should be certified by recognized third-party standards. Nevertheless, Eijgelaar (2011) addresses the importance of prioritising reduction over offsetting.

• Educational efforts: The need for improved education and transparent communication tailored to specific demographics (such as female consumers and younger generations) regarding the environmental impacts of air travel and the potential actions to mitigate these effects. This includes education campaigns to inform about aviation’s climate impacts and the promotion of eco-labels for ticket purchases to aid consumers in making informed decisions. (Büchs, 2017; Eijgelaar, 2011; Gössling & Peeters, 2007; Gössling et al., 2009; Mkono, 2020) Joint efforts are expected from governments, educational institutions, environmental organizations (such as NGOs), airlines, and social influencers. A multi-level approach to education could be particularly impactful: on a fundamental level, basic knowledge of climate change and the environmental consequences of transportation, including air travel, should be implemented into primary and secondary school curricula. In higher education institutions, collaborative projects with NGOs, airlines, and travel platforms could facilitate the development of serious games and short online courses, offering certificates or rewards to encourage participation. On a third level, environmental education should become a standard requirement within professional training programs, particularly targeting frequent flyers, corporate travel managers, and the tourism industry workforce.

• Industry initiatives: A more comprehensive response is expected from the aviation industry to the changing market attitudes, focusing not only on the development of more sustainable practices, such as more fuel-efficient aircraft, alternative fuels, and operational improvements (Eijgelaar, 2011; Higham et al., 2016; Mkono, 2020) but also on actively promoting transparency and incentivizing environmentally conscious behaviour among passengers. As a first step, airlines should publicly disclose per-flight CO₂ emissions both during the booking process and at check-in counters to enhance consumer awareness and enable informed travel decisions. In an additional step, loyalty programs could be redesigned to reward passengers for selecting lower-emission flight options, such as routes operated by newer and more fuel-efficient aircraft. In the long run, the industry is encouraged to invest in and promote the development of innovations in aviation technologies, while communicating progress and associated challenges transparently to the public.

• Promotion of behavioural and structural changes: Suggestions include promoting alternatives to air travel, such as train travel, and encouraging individual responsibility and moral obligation towards reducing air travel’s environmental impact. This is also related to institutional changes to support sustainable travel practices within academic and professional contexts (Büchs, 2017; Eijgelaar, 2011; Mkono, 2020; Schrems & Upham, 2020). Governments, businesses and corporations, academic institutions, environmental organizations (such as NGOs), and the transportation industry (notably the rail sector) are critical actors in facilitating this transition. For example, the integration of multi-modal booking systems that allow users to seamlessly combine air and rail travel within a single platform should be prioritized, making lower-emission alternatives more visible and convenient. Generally, sustained lobbying and investment in high-speed rail infrastructure are necessary, especially in regions where rail could serve as a realistic substitute for flights under a certain distance.

• Psychological and sociocultural interventions: This includes addressing eco-anxiety and guilt associated with air travel through research into psychological dynamics and developing evidence-based coping strategies. Additionally, there is a focus on changing social norms and expectations related to air travel and promoting values of self-transcendence and self-direction towards more sustainable travel behaviours. (Büchs, 2017; Cocolas et al., 2020; Mkono, 2020) This requires joint efforts from academic researchers and psychologists, environmental organizations (such as NGOs), government, educational institutions, and social influencers. To start shifting fixed social norms, targeted campaigns could be launched by NGOs, companies, and the government to showcase that reducing air travel is a common and respected behaviour among admired groups, such as thought leaders, athletes, celebrities, and others.

In general, joint efforts from various stakeholders – including policymakers, the aviation industry, NGOs, and academics – are needed to implement a holistic approach that combines policy, educational, technological, and sociocultural strategies to effectively reduce the attitude–behaviour gap.