The game felt a bit grindy at first until I got the first upgrade then it was a lot more fun.
Also, I needed more than the price of an upgrade to actually purchase it; if it said 10 then it would take 10 points from me but I would need at least 11 to trigger the purchase in the first place (missing a >= somewhere).
The controlling of the paper airline by itself is just plain fun to do. The upgrades give a nice sense of progress.
The little story is pleasantly enjoyable and the choice of music added nicely to it.
Awesome game.