A bit of history to begin with. The technique of using fishing kites to drop a baited line into the water originated with the ancient Chinese.
Later, Pacific islanders came up with similar ideas, for example the Solomon Islanders.
Traditional kites for this purpose also appear throughout the Malay Peninsula. Early forms of these kites were as simple as a large leaf threaded with strips of fine bamboo, with a hook hung from a long length of line.
This form of fishing is still used in some parts of Asia today.
In more modern times, it seems that a certain Captain Bob Lewis was responsible for making this form of fishing more popular in the West. Bob Lewis was active in the sailfish-rich waters off southern Florida, in the U.S.A.
Today, the kites used are mainly simple sleds, diamonds and deltas that are adjusted to fly low. That makes sense since the idea is to take the fishing line out far away from the angler. For example, to get across surf and into deeper water where bigger fish can be caught. Kite fishing is also done out of boats, where the odds of catching a fish are increased by flying more than one kite at once. Commercial kite-based systems have been around since the late 80s.
In really light conditions, keen anglers just attach a helium-filled balloon to their kites to keep them in the air!
The price range seems to be around US$20 to US$150. At the bottom end are small sleds such as the Pocket Sled Kite from Paul's Fishing Kites. The same company sells the Casting Kite in the middle of the price range and their Mega Kite for around US$150.
That's a lot more than for comparable simple recreational kites. But I suppose they have to be very waterproof, and also quite strong in case they get dragged through the water. Or perhaps anglers spend so much on other gear that the retailers hope they can get away with offering pricey kites!
Here's a run down on how kites are used for fishing these days:
The advantages of using 'casting kites', particularly when using live baits include:
Some well-known kites used by anglers include: