These are contractual matters between the passenger and the airline. If the airline refuses to transport a passenger, such passenger may file a lawsuit. It will then be up to a judge and/or jury to make a determination if the airline breached the contract and if so, what compensation it must pay.

It might be worth noting that if the airline "bumps" somebody because of overbooking, it MUST pay compensation. The passenger, however, has a right to sue for damages instead of accepting this compensation.

Furthermore, any provision of the contract of carriage can be challenged in Court as unconscionable.

My point was that we have a right to travel aboard any means of public transportation without government interference.

Perhaps, PatrickHenry can shed some further light on this, since he is an attorney, and I am not.