I hate developers who can't be bothered to write a couple of lines of instructions. This game lets you buy better 'rudder' controls (surely he means elevator) but you have to guess how and when you can use them.
The scoring is seriously wierd. I did level 6 with 4 clicks for 2 stars and 6800 points. Kept trying and eventually managed 3 clicks for 3 stars and 7800. Then I checked the solution video - that gets 3 stars and 7500 using TEN clicks.