U.S. Air Force Tech. Sgt. Aaron Richards, with the 104th Fighter Wing, Massachusetts Air National Guard, inspects the top of an F-15E Strike Eagle aircraft during Red Flag at Nellis Air Force Base, Nev., on Jan. 27, 2012. Red Flag is an advanced aerial combat training exercise held four to six times a year to train pilots from the U.S., NATO and other allied countries in real combat situations.