most of the Non DIY flight control units will do a return to home(spot of take off, generally) in any event that causes the RX to loose signal/fail. now the home build flight controllers are anybody's guess, however, they are in the great minority of what is sold these days.

and just for info,
in all the units i have ever seen, the RX is a stand alone unit and the flight controller is a stand alone unit that plugs into the RX rather like an independently powered servo does. frequency jamming should not have a detrimental effect on the flight control unit. it will just do whatever it is set up to do in the event of signal input loss. in most cases, the flight control is also the RX source of power, not the other way around.