FILE PHOTO: U.S. Air Force F-35A aircraft form up in

FILE PHOTO: U.S. Air Force F-35A aircraft form up in an "elephant walk" during an exercise at Hill Air Force Base

FILE PHOTO: U.S. Air Force F-35A aircraft, from the 388th and 428th Fighter Wings, form up in an “elephant walk” during an exercise at Hill Air Force Base, Utah, U.S. January 6, 2020. U.S. Air Force/R. Nial Bradshaw/Handout via REUTERS.