Airplane inconveniences have been so common that people even coined a term to describe the phenomenon - "Air Rage," which according to Cambridge dictionary is a violent anger directed mainly at inflight airline personnel and arising from the frustrations and stresses of air travel.

Taking into account the air age that appears to be on the rise, a professor from University of Toronto has studied data on up to five million disruptive flights from unnamed large international airlines and found out that the main reason behind the phenomenon is not the awful food or lost baggage but the first-class cabin.

The study, published in the journal Proceedings of the National Academy of Sciences points to a modern plane being a social microcosm of class-based society and a sense of inequality in that small environment lead to people lashing out.

According to the study conducted by researchers from the University of Toronto's Rotman School of Management, there are basically two types of triggers of inequality on airplanes: physical (presence of first class) and situational (boarding location) - both can lead to antisocial behavior by airplane passengers becoming rude or disruptive.

"Physical inequality on airplanes-that is, the presence of a first class cabin-is associated with more frequent air rage incidents in economy class. Situational inequality-boarding from the front (requiring walking through the first class cabin) versus the middle of the plane-also significantly increases the odds of air rage in both economy and first class," the authors, Katherine DeCelles from the Rotman School of Management at the University of Toronto, and Michael Norton of the Harvard Business School

According to the researchers, the chances of air rage occurrence is 3.84 times greater when a first class section is present and 2.18 times greater when there is situational inequality. In terms of flight delay, that's equivalent to 9 hours and 6 hours consecutively.

Furthermore, the study revealed that inequality predicts antisocial behavior in both first class and economy class.

First class passengers, being reminded of their superior status, prompts aggression, Daily Mail notes.

"When people from higher social class backgrounds are more aware of their higher status, they are more likely to be antisocial, to have entitled attitudes and to be less compassionate," DeCelles explained to CNN.

The authors also broke down how air rage differs between first class and economy class.
Incidents in first class were more likely to be the result of aggressive behavior, while air rage in economy class were more likely to result from emotional outbursts.

"People are not trying to get into first class-that's not what we're seeing-we're generally seeing people's emotional reactions, and what could be framed as a frustration reaction. And then being packed into a plane will intensify how you're emotionally feeling and reacting," Decelles told Gizmodo in an interview.

Other factors that result to disruptive behavior of passengers are leg room, number of passengers, alcohol consumption and length of flights. However, their impact was smaller than the researchers expected.

"I expected there to be more support for a lack of leg room as a contributor to air rage, given the attention that leg room has had -- but there wasn't," sais DeCelles in a press release.

The findings can also relate to cruise ships, trains and even office space.