The Singing Sergeants perform during the Smithsonian Holiday Festival at the National Museum of American History, Dec. 5, 2015, in Washington, D.C. The group is one of six musical ensembles that comprise the U.S. Air Force Band, and performed for an audience of approximately 2,000 people. (U.S. Air Force photo by Senior Airman Mariah Haddenham/ Released)

The Singing Sergeants perform during the Smithsonian Holiday Festival at the National Museum of American History, Dec. 5, 2015, in Washington, D.C. The group is one of six musical ensembles that comprise the U.S. Air Force Band, and performed a total of three performances that day. (U.S. Air Force photo by Senior Airman Mariah Haddenham/ Released)

The Singing Sergeants perform during the Smithsonian Holiday Festival at the National Museum of American History, Dec. 5, 2015, in Washington, D.C. The group is one of six musical ensembles that comprise the U.S. Air Force Band, and performed for an audience of approximately 2,000 people. (U.S. Air Force photo by Senior Airman Mariah Haddenham/ Released)

The Singing Sergeants perform during the Smithsonian Holiday Festival at the National Museum of American History, Dec. 5, 2015, in Washington, D.C. The group is one of six musical ensembles that comprise the U.S. Air Force Band, and performed for an audience of approximately 2,000 people. (U.S. Air Force photo by Senior Airman Mariah Haddenham/ Released)