No, it doesn't involve an aeroplane. That would be sensible. No, nor a rocket (which would be less sensible). In parkour you aren't allowed any form of transport apart from your own limbs.
Parkour started off as a sort of assault course used in military training. Parkour does have the advantage that you don't have to assault anyone at the end of it, but on the other hand you may be expected to do more jumping about over city roofs than soldiers usually do except in the more expensive kind of film.
What's wrong with parkour, apart from the occasional possible inconvenience of a foot appearing through your bedroom ceiling?
Well, the word itself is the oddest sort of an object. It's as if someone's taken a French word and then shoved a k into the middle of it just to be awkward.
Though, actually, it wasn't just to be awkward...
Sunday Rest: parkour. This word comes from the French phrase parcours du combattant, which is an obstacle course used for military training. Raymond Belle developed a system of physical training based on this, and called it le parcours. His son David, a stuntman, further refined his father's method, and his colleague the actor and director Hubert Koundé suggested changing the c to a k and deleting of the (silent) s to make the word look stronger and more dynamic...
...which is possibly why every time I see the blasted thing it's like being jabbed by a pin.