GoPro Slingshot
If you want airborne images, the normal answer is to buy a drone. On the other hand, you could just load a GoPro camera into a water balloon slingshot and fire it over the water. You'll need a stabilizing tail as seen here to keep it pointing somewhat straight.
Tail Assembly
The assembly was made out of a piece of packging foam. Split the end that will be opposite the GoPro and compress with a zip-tie to flare it out. Use a 1/4-20 eye bolt on the other end. Feed through and zip-tie as shown. A bolt on the end will allow it to connect to a GoPro tripod mount.
Tail should be made out of buoyant material to keep the GoPro from sinking.
Load, Fire, and Retrieve
Securely attach the GoPro to the tail assembly, then load into the water balloon slingshot and fire! Use a floatie backdoor to keep the GoPro buoyant even if it separates from the tail.
As seen in this image and the video, it helps to have a canine helper to retrieve it for you!