About all I know about fly fishing is that it can be done in fresh or salt water.
That's for sure. I quite like to fish, mostly in saltwater. My favorite fish to catch is called a Snook.
So there is a different rod that must be used, a fly rod?
Yeah a fly rod is different than a spin rod. The point of a fly rod is to cause your lure to land on the surface of the water like a fly.
I find it interesting that many lures are hand tied by the fishermen.  Do you do that?
I've tried it, but it is an art that would take years to master. I know a guy who goes out to a stream in the early morning to see what flies have hatched and ties flies that look like the newly hatched ones.
and a fly line. The fly line (today, almost always coated with plastic) is heavy enough to send the fly to the target. The main difference between fly fishing and spin or bait fishing is that in fly fishing the weight of the line carries the hook through the air, whereas in spin and bait fishing the weight of the lure or sinker at the end of the monofilament or braided line gives casting distance. Artificial flies are of several types; some imitating an insect (either flying or swimming),
Fly fishing
Fly fishing is an angling method that uses a light-weight lure -- called an artificial fly -- to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. The light weight requires casting techniques significantly different from other forms of casting. The flies may resemble natural invertebrates, baitfish, or other food organisms.
Fly fishing can be done in fresh or salt water. North Americans usually distinguish freshwater fishing between cold-water species (trout, salmon, steelhead)