Chicago 'Loop' Pilots assigned to the Thunderbirds, the Air Force's demonstration squadron, perform a delta loop maneuver during practice for the Chicago Air and Water Show over Chicago, Aug. 19, 2016. Air Force photo by Staff Sgt. Jason Couillard SHARE: Download: Full Size (3.52 MB) Credit: Staff Sgt. Jason Couillard VIRIN: 160819-F-TT327-906A.JPG Photo Gallery