@Participant
More years ago than I care to admit, I won a prize in law school for top performance in Aviation Law. I have never practiced that kind of law, but I am an aviation ‘geek’
No airline exists in the USA that does not a Federal operating license. All commercial pilots licenses are Federal, not state (like your drivers license). Planes operate under FARs…Federal Aviation Rules
The FAA governs airline activity and has the power to approve, ground, fly, etc.
Thus all airline operations are subject to all Federal regulations, laws, mandates, etc.
All determination of entry into the country is Federal, now Customs and Immigration is part of ICE.
One cannot be stopped from traveling from state to state by private conveyance (car, boat, walking, private plane), BUT as soon as one boards a public conveyance licensed to carry passengers to cross state lines, then due to the Interstate Commerce Clause in the Constitution all powers belong to the Federal Government.
Now the carrot and the stick moshul.
In the 70s many states lowered the legal drinking age to 18 (NY was already there, but CT and most others were 21). Highway deaths among the young skyrocketed, Congress could not pass a federal minimum drinking age (it was 21 on planes and trains for the control reasons stated above), SO, the Federal Government said to the states if you don’t raise the drinking age to 21, we will cut off all federal highway funds to your state. It worked.