United Airlines appears to have violated their contract with their passenger.
Here is the contract:
https://www.united.com/web/en-US/content/contract-of-carriage.aspx#sec21
Rule 25 is about how passengers may be denied boarding due to oversold flights.
This wouldn't apply because he wasn't denied boarding: he was already seated.
Rule 21 is about the circumstances in which a person can be removed from a flight, and includes a number of issues related to safety. But there is no indication that the doctor was removed because of poor or unsafe behavior. He only started yelling and went limp when they decided to improperly remove him.
And the reason they decided to remove him was for the airline's convenience.
I hope he sues.
= new reply since forum marked as read
And not any old law professor, but a "professor of public interest law at the George Washington University Law School"? 
Are you sure you didn't forget the sarcasm smilie?
If you're serious, please provide a reference. Which law, exactly, says that "you are not allowed to defy or question orders when aboard an aircraft"?
Yes I do know the law better. 49 U.S. Code § 46504 - Interference with flight crew members and attendants. Its 20 years in prison.
Have a nice day!
of how 'they' define boarding goes against the commonly understood and accepted definition of boarding a plane meaning simply to get onto the airplane. So unless the meaning of the airlines jargon is clearly spelled out for passengers before hand, the legal default should be, and I suspect will be, to the commonly accepted dictionary definition, not the airlines insider jargon.
Most industries use jargon that's a bit unique to them but will often go over an outsiders heads. In this case it's not just going over someone's head, it would be using a common term in a way that's different enough that it's misleading to those not in on it.
If "boarding ends when the wheels leave the ground" than my airplane boarding pass should get me onto a plane that's already separating from the stairs/tunnel, taxiing down the runway or in the que for take off... but dollars to donuts it won't... nor should it. 
Their legal knowledge simply by watching Judge Judy.
She arbitrated a case where a roofer claimed that the terminology he used (I think it was "re-roof" was understood throughout the industry to mean putting a new roof on top of an existing one. But the plaintiffs, his customers, thought he would tear off the old roof first, then construct the new one. She used exactly the same reasoning in telling the roofer that he was wrong--that where a term could reasonably mean something different to a layperson than what he believes the industry to intend, it was his responsibility to spell out exactly what the term meant.
Obviously we know she's not a Supreme Court Justice and TV is not a real courtroom. The point is this principle is exactly the same as you described it, with a great source--and she is a trained attorney and was "real" judge for a long time, so she probably wasn't hallucinating the concept.
Anyway, we're on the same page about this now.
