A Bulgarian air force SU-25 Frogfoot aircraft taxis past a U.S. Air Force C-130E Hercules aircraft at Bezmer Aviation Base, Bulgaria, March 31, 2008, prior to flying a sortie for exercise Thracian Spring 2008. The annual bilateral training exercise between the United States and Bulgaria provides training and improves interoperability between the two nations. (U.S. Air Force photo by Master Sgt. Scott Wagers) (Released)