The world's first nesting performance kayak may not actually reduce to airplane carry on size.  But its 6 interconnecting sections pack into a custom-made wheeled backpack bag that's a mere 3 feet long and weighs only 55 pounds.   So you can store it in a closet.  Then roll it like a piece of luggage and take it with you in a car trunk, a cab, train, ferry, check it on your flight, or even carry it on your back...