FILE PHOTO: Three F-35 Joint Strike Fighters flies over Edwards Air Force Base

FILE PHOTO: Three F-35 Joint Strike Fighters flies over Edwards Air Force Base

FILE PHOTO: Three F-35 Joint Strike Fighters, (rear to front) AF-2, AF-3 and AF-4, flies over Edwards Air Force Base in this December 10, 2011 handout photo provided by Lockheed Martin. Darin Russell/Courtesy of Lockheed Martin/Handout via REUTERS