Airmen from the 86th Airlift Wing salute during the lowering of the German flag Sept. 9, 2016 at Ramstein Air Base, Germany. The Airmen were participating in a 9/11 Memorial Retreat Ceremony to honor the 2,977 lives lost during the attacks. (U.S. Air Force photo/Senior Airman Tryphena Mayhugh)

Two 86th Airlift Wing Airmen hold a folded American and German flag during a 9/11 Memorial Retreat Ceremony Sept. 9, 2016 at Ramstein Air Base, Germany. 2,977 people lost their lives and over 6,000 were injured during the attacks, resulting in one of the largest domestic terrorist attacks in U.S. history. (U.S. Air Force photo/Senior Airman Tryphena Mayhugh)

From left, Senior Airman Daneeka Mucker, 86th Logistic Readiness Squadron hazmart pharmacy specialist, and Senior Airman Anthony Tepen, 86th Vehicles Readiness Squadron vehicle maintenance technician, fold the American flag during a 9/11 Memorial Retreat Ceremony Sept. 9, 2016 at Ramstein Air Base, Germany. 2,977 people lost their lives in the attacks, including 343 firefighters, 72 law enforcement officers and 55 military personnel who were first responders at the World Trade Center. (U.S. Air Force photo/Senior Airman Tryphena Mayhugh)

Master Sgt. Jesse Burkard, 86th Civil Engineer Squadron fire protection superintendent, lays a wreath during a 9/11 Memorial Retreat Ceremony Sept. 9, 2016 at Ramstein Air Base, Germany. 2,977 people lost their lives and over 6,000 were injured during the attacks, resulting in one of the largest domestic terrorist attacks in U.S. history. (U.S. Air Force photo/Senior Airman Tryphena Mayhugh)

From left, Airman 1st Class Bria Jackson, 786th Civil Engineer Squadron emergency management specialist, and Senior Airman Daneeka Mucker, 86th Logistic Readiness Squadron hazmart pharmacy specialist, lower the American flag during a 9/11 Memorial Retreat Ceremony Sept. 9, 2016 at Ramstein Air Base Germany. On Sept. 11, 2001, 19 hijackers overtook four commercial airliners, crashing two into the World Trade Center towers in New York City, New York. (U.S. Air Force photo/Senior Airman Tryphena Mayhugh)