Hi,
Chavaliers du Ciel caused quite a stir in the film and TV industry when it was produced in '04, because it's the first time since Top Gun that any production company has been willing to spend enough money to "gaffer tape" a camera onto a military aircraft. The cameras were mounted in repurposed fuel tanks and the camera system was manufactured, doubtless at pan-galactic expense, by Dassault Aviation.
My experience with this is limited to handholding in a helicopter, occasional Tyler mount stuff (typically used in American news-copters, and the like) and watching, in awe, from afar, as someone mounts a Wescam stabilised head on a Jetranger. The problem is not physically making it work, the problem is making it legal, insurable, and safe, especially on a high performance aircraft. I can't even stand a tripod on the floor of a helicopter without incurring a lot of paperwork.
The other problem is that if you are shooting video and you want to perform a high-G manouvre, it tends to pull the tape away from the head drum and give you a duff recording. Film cameras do better but it still needs an enclosure controlled for pressure, temperature and humidity.
Generally very tricky to do.
Sorry to waffle on, hope it's of some interest.
Phil