LAKELAND, Fla., Apr. 3 The grand prize in AOPA's Centennial of Flight Sweepstakes made its debut at the Sun 'n Fun EAA Fly-In in Lakeland, Florida, this week. AOPA members at the show flocked to see the pristine 1940 Waco UPF-7. The three-seater biplane has undergone more than a year's worth of restoration at Rare Aircraft in Minnesota and is now valued at some $250,000. It will be awarded to a winner in early 2004. New and renewing AOPA members are automatically entered to win the airplane. For details on the sweepstakes and the restoration project, see AOPA Online. The airplane will also appear at the AOPA Fly-In in June, EAA AirVenture in July, and AOPA Expo in October.