U.S. Air Force Lt. Col. Jason Koltes, Thunderbird 7, Operations Officer, U.S. Air Force Air Demonstration Squadron Thunderbirds, signs an autograph for a Bulgarian air force airman during the Graf Ignatievo Air Base Air Show, Bulgaria, June 25. The Thunderbirds will perform in nine countries during their six-week European tour, fostering international goodwill and representing America's airmen around the globe.