> "What is an authority for someone is a criminal for another (see certain regimes)"
What does this have to do with air travel? This person isn't fighting tyranny, they're being asked to leave a plane. The authority is the same for everyone that participates in that state, airport and aircraft.
> "the airline is not an authority under the law"
No, but it can call authorities just like you can call the police when required. Also airports and aircraft do operate under different rules for security.
> "you have made 25 flamewar comments in this thread"
My comments are not "flamewar" because you disagree with them. I've always posted civilly in the face of very harsh and rude replies and will continue the discussion as long as I want. I advise you leave the moderation to the admins here.
Nope, not "at any time" or for "any reason". Air companies are subject to several regulations, and another person posted it here: after boarding there are pretty specific reasons for why you can expel someone, and "because I say so" is not one. Not to mention that planes fly so you obviously can't "surprise deny" service at "any time".
At hotels you also can't throw people out on the street in the middle of the night, unless they did something wrong. Which is clearly not the case.
You also cannot throw out tenants without reason and without proper proceedings, for example.
Anyway, you have made 25 flamewar comments in this thread. Posters that do that are usually banned so I would advice you to stop. (just a friendly advice)