I think in reality they are names of pilots serving on the squadron, and pilots do not neccessarily fly their "own" aircraft.
Certainly in USAF their would be a Crew Chief (ground crew) who looked after one particular plane but I have no idea whether that is true in the RAF or not - although you do see ground crews names on them too - on gear doors and such like.
I thought pilots found their plane by seeing which key worked in the ignition
G