A 1988 arcade game by Sega.
The idea of the game is to pilot a helicopter around towns and canyons and against "boss targets" like ships and such. You could shoot missiles and with machine gun, preferrably at everything that moves (or doesn't move but tries to shoot back). Not entirely realistic because the chopper carries way too much ammunition... =)
What makes the game interesting is that it was full 3D. There were two major viewpoints for the symphony of destruction, above and behind the helicopter. And here's the kicker: In the "above the helicopter" mode, you still could control the flying altitude - but instead of your copter shrinking and growing, the rest of the screen did.
That did look pretty nifty on arcade screen. Triply so on Commodore 64 (even when in C64 version the buildings seemed incompletely built...)
Usually the levels were three-part (at least the first one, and probably the rest of them too): First one was top-down, the second with the behind view, and third top-down against the "boss".
(Oh yeah, it's One Of Those Games With Ever-Memorable "Game Over" Music! I particularly like the C64 arrangement...)