I've been involved quite a few air-to-air photo shoots. They're a bit of a blend of photographic techniques - to a certain extent you can pose the subject by frantically waving a series of hand signals. You can change the lighting (the sun's relative position), by re-positioning the formation and although you can plan things on the ground there's often an unexpected element so there's a bit of sports photography in there too.
With good light, some interesting landscapes, a team of good pilots and a comfortable camera ship things are pleasant, with grey flat light, complex airspace, pilots not at the top of their game and an awkward camera ship things can get challenging.
The picture above was taken during a shoot that had its fair share of challenges (most of them do), but the light, pilots and camera ships weren't among them.