There are more planes in the ocean than there are submarines in the sky
AT first glance, this looks like it might be true. But...
Consider that there are more planes than subs (probably) altogether. When you consider it on a percentage basis, or a 1-out-of-a-thousand basis, it might not be true.
After all. Where does the sky start? Isn't it at the earth's surface? This means that all the subs that are floating at the surface of the water, are in the sky as well as in the water. In addition, the ratio changes when a sub dives. After all, it's seldom that planes in the ocean ever surface again... although a few might be in tide waters, and a few might be raised by curiosity seekers.
It's gonna take more research to prove it one way or the other.