An F-22A Raptor and a World War II-era P-51 Mustang fly over Tucson, Ariz., Sunday, March 5, 2006, during the 2006 Heritage Conference. The conference combines different U.S. aircraft from more than 60 years of aviation history to ensure certification in performing air shows...

An F-22A Raptor and a World War II-era P-51 Mustang fly over Tucson, Ariz., Sunday, March 5, 2006, during the 2006 Heritage Conference. The conference combines different U.S. aircraft from more than 60 years of aviation history to ensure certification in performing air shows...

Two F-15 Eagles fly alongside an F-22A Raptor and an A-10 Thunderbolt II over Tucson, Ariz., Sunday, March 5, 2006, during the 2006 Heritage Conference. The conference combines different U.S. aircraft from more than 60 years of aviation history to ensure certification in...

An F-22A Raptor from Langley Air Force Base, Va., and an A-10 Thunderbolt II from Pope AFB, N.C., fly over Tucson, Ariz., Sunday, March 5, 2006, during the 2006 Heritage Conference. The conference combines different U.S. aircraft from more than 60 years of aviation history to...

An F-22A Raptor from Langley Air Force Base, Va., flies in formation along with a P-51 Mustang over Davis-Monthan Air Force Base, Ariz., Sunday March 5, 2006, during the 2006 Heritage Conference. The conference combines different U.S. aircraft from more than 60 years of...

An F-15 Eagle and a P-51 Mustang fly in formation along with another P-51 Mustang over Davis-Monthan Air Force Base, Ariz., Sunday, March 5, 2006, during the 2006 Heritage Conference. The conference combines different U.S. aircraft from more than 60 years of aviation history...

Lieutenant Col. Michael Shower, an F-22A Raptor pilot, taxis by the air traffic control tower, after landing Friday, March 3, 2006, at Davis-Monthan Air Force Base, Ariz, during the 2006 Heritage Conference. The conference involves today's state-of-the-art fighters flying in...

An F-22A Raptor from Langley Air Force Base, Va., flown by Lt. Col. Michael Shower takes off Friday, March 3, 2006, at Davis-Monthan Air Force Base, Ariz., during the 2006 Heritage Conference. The conference involves today's state-of-the-art fighters flying in close formation...

An F-22A Raptor from Langley Air Force Base, Va., an F-4 Phantom from Holloman Air Force Base, N.M., an F-16 Fighting Falcon and an A-10 Thunderbolt II fly in diamond formation over Tucson, Ariz., Sunday, March 5, 2006, during the Air Combat Command Heritage Conference at...