Taping it to inside of an unscratched chin window is an option but it wil be a bugger to turn on. If you are dead keen buy a nackered chin window and cut a 20mm diameter hole in it.
Think laterally about application of the rules governing what is baggage and you may find a spot to legally "stow" it for the flight that also gives you a good shot.
Use tape and a saftey wire, don't rely on a suction mount.
Maybe make a clip mount to fit it on a sliding window?
Another legal possibility is to modify a piece of ancillary equipment that is attached to the aircraft by bolting the camera to it rather than directly to the aircraft. In this case spend a few quid on some custom machining (not onerous given the size of the gopro) to make the thing look and act like it is fit for the job.
BTW, Gopros dont work too well on skids. They have a rolling shutter which exaserbates vibration creating what is termed the "jello effect".
Mickjoebill