A 'Fight Club' meme slamming United captures a disturbing truth about airlines and people who fly coach

The Internet is in an uproar after a United Airlines passenger, 69-year-old doctor David Dao, was physically dragged out of his seat by authorities on Sunday evening. One popular meme making the rounds on social media depicts United's coach class as the "fight club," and it hints at a larger strained relationship between airlines and their coach-class passengers.

The strong reactions United is facing from the public - which has resulted in its share price tanking and many calling for a boycott of the brand on Twitter- illustrates growing resentment between airlines and customers as they pare down the experience for economy passengers. 

Flying coach often is an unenjoyable experience, between cramped legroom and increased carry-on restrictions. But there's also a simple economic reason why flying coach may feel worse than ever.

Coach flyers are often infrequent, and they are much less meaningful to an airline's bottom line than higher-paying customers. 

At United, for example, 85% of customers fly less than once a year and they account for close to 50% of revenue, United president Scott Kirby told analysts in October. These numbers are similar at other airlines, like American.

This means that just 15% of United's customers - essentially everyone not flying coach - account for half of its income. 

A large chunk of the remaining revenue comes from a small group of frequent business flyers who pay full price premium or economy cabin fares. 

As a result, airlines have added perks to premium cabins while they've pared down in coach. 

For example, Delta now offers bargain hunters a low-cost offering called Basic Economy which does not allow customers to pre-select seats or make changes to their itineraries. 

Both United and American Airlines have introduced a low-cost basic economy fare class, which does not allow passengers to bring carry-on items for the overhead bin. 

The strategy seems to be paying off monetarily - United Airlines reported a profit of $965 million with pre-tax earnings of $1.5 billion for the third quarter of 2016. 

But it may also be leaving the majority of customers feeling more jaded than ever.