We have a law called the Posse Comitatus Act that specifically forbids the use of federal troops for law enforcement. It was passed because deploying troops in American states puts too much power in the hands of the President.

We already do have such a "paramilitary force", called the National Guard, which is under the control of the governors. It can be deployed federally when called on by Congress.

The President can also do it, in a state of emergency, but this President declared a state of emergency the moment he took the oath of office. If you genuinely believe that the nation is in a constant state of emergency, now and forever, then perhaps it's time to reconsider much more than just who is running the airports.