You’re probably right but the plane was in the North East.
I haven’t read the whole thread and it’s probably been discussed already, but my major gripe on the ‘believability’ front is the way ATC actually works.
Radio communications to aircraft are not closed and secure systems. Anyone who is tuned in to the right frequency and has a VHF radio can talk to aircraft. This idea that you could lock out ATC and no one could contact them is bogus.
Beyond that, an aircraft would not have left the ground with a plan to land at a particular runway, so this idea that he’d be surprised at a change is also bogus. The regional ATC they hacked into wouldn’t even have been the one to give landing instructions, they’d have transferred the plane to the local ATC tower.
Now, there is a certain amount of vulnerability to mayhem created by simply disrupting conversation... heck, even a stuck mic can cause problems, but that’s a different problem.