[blackdog]

For a few months out of each year the giant rays migrate for some reason off the coast of Florida. I can see them from my plane. Sometimes there are hundreds of them flying along just under the surface. They have to have a wingspan of fifteen to 20 feet to stand out at 5,000 feet above. Very cool creatures.

[Jeff Chandler]

When you come upon a big one unexpectedly, first you startle it, then it startles you as it rises from its camouflage in the sand.

Time to rinse out your wet suit, LOL!

[Robert DeLong]

Since bat rays are supposedly limited to the West Coast Pacific waters between Oregon & the Gulf of California, and also the Galápagos Islands, I'm wondering if what you are seeing are not really Manta rays. Their "wings" can span up to 23 feet in length. The furthest from the equator they have been recorded is North Carolina in the United States.