Flight Control is a very nice time killing game and it has actually everything it needs to be perfect in its genre: a nice diversity in difficulty, different maps and planes with additional features, highscores and statistics... and the addiction level.
You can easily try something more difficult if you think you are improving in the game or on the other hand something easier if you are a beginner. The variation and differences in maps and planes are different at each difficulty. Additions such as the wind system, the stunt map or just more kind of planes are good examples for the differences in playing. The highscores and statistics are good additional features.
If you are getting more skilled, this game can be quite more than just time killing ;)*
*I have not played this game that much on PC but I did on iOS.