I think the question boils down to "Do they have the legal authority of police or not?"
I find it irritating that people will throw out smokescreens like "They are not the police, they are private security guards" and such.
If someone wants to make a point that hinges on a particular fact, they ought to make sure at least that the particular fact their point hinges upon is true.
I also find it unlikely that the "Aviation Police" won't have the legal authority to remove passengers designated as unwanted or disruptive. That would make no sense to me.
Haven’t really been following the story, but the alderman in charge of the investigation said “my understanding is they may not be allowed on a plane.” Probably there’s a tangle of FAA and other regulations, but that seems to have sealed the firings and settlement.
You just found it unlikely then. They have no authority to make arrests. They have limited authority to detain. They are not authorized to carry weapons or firearms. Their authority to remove someone stopped when the passenger said no. They probably were authorized to board the plane, ask the passenger if he would voluntarily give up his seat and leave the plane. The passenger said no, he would not. That should have ended their involvement in the incident. But it did not. They took it upon themselves to assist him off the airplane. As a result thus far, the three that helped him off the airplane are on suspension waiting to hear if criminal charges will be filed against them, their boss is out of his job, and United Airlines wrote a check with a bunch of zeroes to the right of what was probably a double digit figure. And the doctor will probably be able to tell the changes in the weather for the rest of his life. Who won? In my opinion, only the lawyers. Could it have been prevented? Definitely. There probably were many other passengers that would have gladly accepted the offer made to the doctor, but in the view of the three thugs that thought that they were sworn police officers and later learned that they were not when their superior said to them,”You are suspended until further notice”, the doctor had defied them and had to be taught his place. Three elephants should never engage in a shitting contest. Very little good ever becomes of it.