The fish swims through the water then broaches the sea-surface and flies (although “coasts” is probably a better word) through the air until gravity wins, as it always does, and the fish re-enters the water.
The resistance of air being less than that of water, the fish will travel further in the air than it would in the water.
Now think of yourself as a sea-bound shark chasing the flying-fish. You are bopping along at, say, ten knots when, to your amazement, your prey disappears, only to re-appear seconds later significantly far ahead of you.
How can that be?
One minute you are both bopping along at ten knots, you are only five feet behind and gaining, then five seconds later you are both still bopping along at ten knots, but you prey has temporarily disappeared and then re-appeared forty feet in front of you.
If you asked a marine-based consultant – a brainy dolphin for example – you might be told that the flying-fish had mastered the art of time-travel by making use of another dimension. A worm-hole in space.
As a shark you find that hard to believe, because you have no concept of traveling through the air.
As a human, familiar with both the sea and the air, it all makes sense.
But as a human you are bound to have problems comprehending the fourth dimension. Or the fifth.
You may also have problems comprehending the slowness of the world’s fastest typist when compared to the slowest computer still in operation on the planet, or the way of life of executives on the golf course.
That doesn’t make them less real.