Background. Seating is one of the major factors that can affect airline passengers’ comfort or discomfort in-flight and their behavioural re-purchase intentions. There has been a rise in dis/comfort issues in economy class and related health problems – especially for long-haul passengers, including individuals of tall stature and large size who may suffer most from the shrinkage in space in aircraft economy cabins. There is a scarcity of research on the relationship of the anthropometric measurement of airline passengers (e.g., Body Mass Index (BMI) and seat dis/comfort, and passenger satisfaction and future flying intentions with the same airline for long-haul flights. Purpose. The purpose of this study is to examine elements of aircraft seat comfort and discomfort that affect long-distance air travellers through an understanding of their experiences in economy class and the impact of these experiences on their intentions of flying again with the same airline. In addition, the research seeks to focus on the segment of the airline market that has so far been ignored (that is, passengers of size), looking at their experience in-flight with seat comfort and the impact of this on their future flying intentions. Method. A quantitative method has been conducted with participants from the USA (N= 168), who completed an online survey assessing past experiences of seat comfort and discomfort during a long-haul flight in the economy cabin, together with their pre-existing expectations, their satisfaction with the flight, and behavioral intentions to re-fly with the same airline. Result. The overall result of the study shows that the seat dis/comfort experience is predictive of passenger satisfaction; this effect is partially mediated by fulfillment of expectations. Furthermore, fulfillment of expectations is more predictive of re-flying intentions than is satisfaction. BMI and ethnicity functioned as moderators to the mediating effect of fulfillment of expectation on the relationship between the seat dis/comfort experience and passenger satisfaction. This moderation effect was greatest for passengers of higher BMI. Length of flight, the purpose of flight, gender and age did not play a moderating role. Regarding features ofthe economy class seat, there were lower levels of satisfaction with the seat recline, footrest and legroom amongst long-haul passengers. Conclusion. The outcomes of this study can assist researchers, airline managers and marketers when taking steps to enhance the in-flight experience for economy class travellers on long-haul air trips, especially for customers of size.