As a Navy aircrewman on an antisubmarine plane, I saw all sorts of stuff on or in the ocean. That was part of my job, and we flew at only 200' above the water. But the ocean distorts the view of things underwater, and you can see something at an angle you wouldn't expect. I'd say the guy probably saw a white fish, maybe some form of ray.

I never saw ayn tic-tacs. Sometimes things are hard to identify, but that doesn't make them UFO's. I've also flown low over land as a civilian search-and-rescue crew member. It's amazing how much stuff I see that I want to go out and investigate later, because I can't figure out what it is.