Seek and Destroy

In this game, you control a tank of the Proton Kingdom fighting against the Q-stein invaders. You have to go from one enemy stronghold or conquered city to another, destroying the enemies inside. The further into the game you get, the more types of tanks you can select. There are 15 types overall. Also, as you advance, you can customize your tank with stronger weapons like nuclear missiles and flight ability. Yes, your tank can fly, if you upgrade. (Mobygames)