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.
Step 1: 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.
Step 2: 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!