One of the guises state police operate under in America is the "highway patrol"—a force that searches for terrorists and drug trafficking and the like.
And presumably, air travel is a privilege, not a right, just like driving a car is. (Or is it? Taking public transit is a right that can't be denied to someone unless they explicitly break a rule of the system. But airports are private companies...)
So, given that, is there a legal reason that there is no "airway patrol"?
I'm not suggesting they have the powers of random search & seizure that the TSA seems to have, mind you. But should there be state police that are stationed at airports, who search people when they have probable cause?