Kind of a reverse Payne Stewart..
Huh? If you mean sneak on board, take out the pilot, then install a remote control device and bail out of the plane while some other conspirator(s) take control from the ground, I'd say you've watched too many James Bond movies.
How about...suicide bomber charters a flight, kills the pilot (or IS the pilot, having rented the plane), and drives it into a building? Think that one is more plausable? (Hint: 9/11, teenage pilot, dozens of suicide bombers in Israel, ...)
We're not dealing with a particularly high-tech group here. We're not dealing with people who want to live a long life, and who have money and training and motivation to construct complex high-tech devices & schemes reminiscent of James Bond. These are people who are content to live in caves and kill themselves in the hope that they might take someone with them.