A kite in hand can be paper, plastic or nylon, square, round or rhomboid.

A kite in flight is a sail in the sky, riding invisible currents of air into the heavens or a misplaced tree.

The choice of kites depends on what you want to pay and how you want to play. You have less choice in where to fly it. A basement apartment is rarely as uplifting as your neighborhood park.

Some favorite kite-flying spots are the Monument Grounds, Carter Barron, Rock Creek Park, Bull Run Regional Park and Carderock. But there is some debate about which skies are friendliest to high-fliers.

Stuart Landau, a local physician and avid kite-flyer for the last 20 years, thinks parking lots and schoolyards make the best kite- flying areas. "The problem with parks," said Landau, "is that you have to worry about trees."

The Smithsonian's Paul Garber, 82 years old and probably the foremost kite expert in the country, disagrees. "In the city," he said in the 1976 instruction manual for the annual kite carnival, "it might come down in a street and become a sudden startling hazard to a motorist."

So much for kite controversy. Even in these highrise times, finding open sky should be no problem. But first you have to find a kite.

There are two alternatives -- buy one already assembled or make your own. If you like the convenience of a store-bought kite, there are hundreds of varieties to choose from.

Below is a list of stores. But first, some tips from local enthusiasts:

1. Never run with a kite -- you might fall in a ditch.

2. Never climb a telephone pole to retrieve a kite tangled in the wires.

3. If your kite disappears in a lake, let it go. Soggy kites do not great flyers make.

4. Never fly your kite at Hains Point; it might wind up a permanent fixture on an airplane.

5. Finally, this advice from Paul Garber on how to signal your kite-launcher when it's time to launch. "When I fly with my wife, I shake my leg so she knows when to release it."

SPECIALTY SHOPS

THE KITE SITE -- 3101 M Street NW. Already-made kites from $1.95 to $200. Kite-making accessories. Call 965-4230.

KITES AWEIGH -- 6 Fleet Street, Annapolis. Already- made kites from $4.95 to $125. Kite-making accessories. 301/268-6065.

THE KITE LOFT -- 301 South Light Street, Harborplace, Baltimore. Already-made kites from $4.95 to $150. No accessories. Soon to be available: Kites to Make and Fly, by David Pelham. An oversize book (14i x 18i) with punch-out materials to make ten kites; $14.95. 301/528-0888. FAMILY BICYCLES -- Hampton Mall Shopping Center, 9183 Central Avenue, Capital Heights. Already-made kites from $3.50 to $39. Kite-making accessories. 350-0903. SMITHSONIAN MUSEUM SHOP -- National Air and Space Museum, Seventh and Independence Avenues SW. Already-made kites from $1.49 to $200. No accessories. Available now: David Pelham's punch-out kite-making book, Kites to Make and Fly, $14.95. 357-1387. A KITE MAGAZINE To subscribe to Kitelines, a quarterly magazine for kite-flyers, write to 7106 Campfield Road, Baltimore 21207, or 301/484-6287. A subscription is $9 a year.