A US Air Force Stealth fighter F-22 Raptor takes off from Kadena Air Base on the southern Japanese island of Okinawa, Aug. 14, 2012. A group of F-22s arrived in Okinawa in late July, their first deployment overseas after the easing of flight restrictions imposed in mid-May because pilots reported dizziness and other symptoms of hypoxia. Greg Baker/AP
A pilot's outfit is displayed during a news conference at the Pentagon July 31, 2012, to provide an update on the Air Force Scientific Advisory Board's study into life support systems installed on the F-22. Manuel Balce Ceneta/AP
An F-22 fighter jet flies over Joint Base Elmendorf-Richardson in Anchorage, Alaska, Aug. 1, 2010, during the annual Arctic Thunder air show. A search is under way for an F-22 from the base that has been missing in the state’s interior. M. Scott Moon/Peninsula Clarion/AP
Vapor forms above the Raptor flown by a pilot of the Air Combat Command F-22 Demonstration Team at Joint Base Elmendorf-Richardson, Alaska, on July 26, 2012. Defense Secretary Leon Panetta approved a plan to lift flight restrictions following the ongoing correction of oxygen-deficit problems. Bill Roth/The Anchorage Daily News/AP
An F-22 Raptor aircraft deploys flares over Kadena Air Base, Japan, Jan. 15, 2009. Clay Lancaster/USAF/Reuters
An F-22 Raptor sits in front of a hanger at Kadena US Air Force Base on Japan's southwestern island of Okinawa June 16, 2009. Yuriko Nakao/Reuters
A Raptor prepares to take off at Kadena US Air Force Base on June 16, 2009. Yuriko Nakao/Reuters
An F-22 Raptor executes a supersonic flyby over the flight deck of the aircraft carrier USS John C. Stennis in the Gulf of Alaska June 22, 2009. Ronald Dejarnett/US Navy/AP
A ceremony at the Lockheed-Martin plant in Marietta, Georgia, marks the delivery of the first F-22 jet to the Pacific Air Force Feb. 2007. Courtesy of the Pacific Air Force
An F-22 Raptor fighter plane flies over during a display at the Farnborough aerospace show in Farnborough, England, June 14, 2008. Lefteris Pitarakis/AP
An F-22 Raptor performs at the N'Awlins Air Show in Belle Chasse, La., Oct. 26, 2007. Alex Brandon/AP
A pair of USAF F-22 Raptors fly over the airport during the Sun n' Fun Fly-In at Lakeland Linder Regional Airport in Lakeland, Fla., on April 7, 2006. Pierre DuCharme/The Ledger/AP
Two F-22 Raptors fly behind a KC-135R Stratotanker aircraft after inflight refueling during a training mission off the coast of Florida April 2, 2007. Thomas Meneguin/USAF/AP
US jets to South Korea: The US sent F-22 stealth fighter jets to South Korea to join military exercises as North Korea threatens war. The US has also sent B-2 bomber jets to South Korea.
ByPaul Eckert, Reuters
The United States sent F-22 stealth fighter jets to South Korea on Sunday to join military drills aimed at underscoring the U.S. commitment to defend Seoul in the face of an intensifying campaign of threats from North Korea.