U.S. Air Force Senior Airman Nick Kester (left), with the 23rd Logistics Readiness Squadron, and British Royal Air Force Senior Aircraftman Christopher Harris, with the No. 9 Squadron, refuel a British Tornado GR4 aircraft during Red Flag 11-3 at Nellis Air Force Base, Nev., on March 1, 2011. 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 for real combat situations.