In contrast to the game guessing thread, this is for actually identifying a game you remember vaguely, but the name escapes your memory.
I remember playing something on the NES, on one of those "X number of games in one" pirate carts. You controlled an aircraft, probably a helicopter. The camera was top-down perspective. The color scheme was pretty dark, mostly blue. Player 2 would control all the enemies (aircraft, cannons, ships) to try and take the other player down. The field of vision was pretty limited, since the camera would follow player 1's unit tightly.
https://www.youtube.com/watch?v=YZudVNf7hN0
Maybe Raid on Bungeling Bay? Maybe not.
I think it may have been exactly that. The sound effects certainly ring a bell (heh) and the color scheme is dead on. In my memory it was a bit more fast-paced, but meh. Memory lies all the time.