You have to just keep killing them and let the blimps get to the other side of the city. When I beat it, 1 blimp was destroyed and I still finished. Only 1 out of 3.

you **** *****

i know its hard...so i came up with this....keep the blimps from catching fire...and here
is a awesome tip:

for the dragons that breath fire, freeze them in mid air..then ram them, (target...then
super fast, fly into them)and they're dead.

for the ones that breath "ice" , you just simply fly tworads the sky..then shoot them down
with lazers vision