Some of the pictures were from satellites, not airplanes.
Above view
The object taking the picture can be underneath you, relative to your position on the planet.
Sky view
The pictures are all of the ground.
Photo view
Top-down view.
They used to have a three quarters view where the airplane dataset extended.
That was actually my only reason to use Bing maps, they had an impressive 3/4ths view where you could change the angle.
Overview
Overlook
"Aerial" isn't directly related to airplanes. It means in the air. Unless you consider low earth orbit outside of the atmosphere, which is somewhat debated.