Good luck trying to find a session. ALL the pilots are mad because Gopro stopped making them so they are rarer by the day. You have people snatching them up fast as they can to either profiteer or to have them because they are pro pilots who regularly use them.
Talk about a company shooting their own feet...
Walmart has a good selection of cameras small enough to be used on quad copters and planes. A lot of them are under 50 dollars and can usually do 1080p x 30 fps. Some will do better resolutions then that.
Runcam also makes the split for ~ 80 dollars that is hard mounted IN the quad and safe. They do reasonably good footage as well. This is from a Runcam split V1 in my Alien. Don't mind the grainyness.. That is a combination of my poor editing skills and not knowing how to properly convert video where it does not lose resolution and the normal hit I take on all my videos with Google doing what ever they do to crapify the resolution. This is 1080P 60 fps and is clear as a bell on the original and on my computer.