I can't swim and I hate deep water. If the engine cut out and there was no land I would die of a heart attack before touching the water!
Simple way to handle this concern: Don't fly over water.
I took three new firefighters in our fireboat for marine training last year. As a par tof the training, I had each lean overboard to recover an object form the water. One fellow then declared he could not swim. Silly me, I had never thought to ask!
Now, we have a swim program, If you can't do 15 minutes with no lifejacket, unassisted, you cannot be marine qualified. There we were, all the old guys, in the pool, proving we could do it too, after all these years! We all passed. No new hires who cannot pass the swim test.