With state sponsored terrorism, the risk isn't that the Feds will put the agent away forever, it's that the USG (and, incidentally, other particularly allowed countries) will identify that it is state sponsored terrorism and treat the attack as exactly what it is—simultaneously and act of war and a gross violation of the laws of war.

What kind of state sponsored terrorism? Black ops programs? Air forces dropping bombs? Assassinations and decapitation strikes?

Or are we talking about the boogieman that is an excuse for all sorts of paranoid crackdowns, expenditures, and questionable legislature?

Who exactly are you afraid will sponsor radio jammers at airports, and why do you think they will do so?

actually, I'd think state sponsored terrorism would have the resources to get away with it.

Just send the voice data through a raspberry pi to a remote location and carry out the attack from there. You could send voice data through a TOR-like protocol or something to keep you anonymous, if that's important. You could maybe rig some explosives to go off if the FBI/FCC/FAA gain access to the attack point, to prevent them from recovering evidence.

Lot's of police/fire radio systems are similarly without authentication, so you could amplify the mayhem by doing the same thing to those frequencies.