Potential suspect of Terrorist Attacks AKA Cessa, is a little plane that holds up to 2 people, a pilot and a passenger. It can fly really high and will fall if you just go all the way straight up.
Personally, i use this plane to escape cops when i just grow some
drugs snow and trees.
Very useful and resistant to bullets [not that resistant against rockets] but very difficult to land, due to the lack of countryside on the map. (Excepting airport)
The plane can be found in the higher up left (blue one) and in the higher up right (red one) part of the map, just in the airport.