The U.S. Air Force Thunderbirds air demonstration team performs the Delta Loop maneuver during a practice show in Kalispell, Mont., Aug. 29, 2014. The U.S. Air Force Thunderbirds air demonstration team performs the Delta Loop maneuver during a practice show in Kalispell, Mont., Aug. 29, 2014. SHARE: Download: Full Size (1.8 MB) Tags: photo essays Credit: VIRIN: 339772-V-UCS98-568.jpg Photo Gallery