U.S. Air Force Master Sgt. Sharon Nichols, Air Combat Command Directorate of Air and Space Operations command and control manager, Col. Steven Fino, 1st Fighter Wing vice commander, and Senior Master Sgt. Vanessa Johnston, ACC Intelligence Directorate, 1A8XX Air Force Specialty manager, lay a wreath during the POW/MIA 24-hour Recognition Run closing ceremony at Joint Base Langley-Eustis, Virginia, Sept. 21, 2018. As of Aug. 29, 2018, the number of Americans missing and unaccounted for from the Vietnam War is 1,594. (U.S. Air Force photo by Airman 1st Class Anthony Nin Leclerec)

Retired U.S. Air Force Col. William “Blister” Townsley delivers a speech during the POW/MIA 24-hour Recognition Run opening ceremony at Joint Base Langley-Eustis, Virginia, Sept. 21, 2018. Townsley spoke about being shot down while flying a Cessna O-2B Super Skymaster during the Vietnam War. (U.S. Air Force photo by Airman 1st Class Anthony Nin Leclerec)

(From right) U.S. Army Col. Edward Vedder, 633rd Air Base Wing vice commander and U.S. Air Force Senior Master Sgt. Vanessa Johnston, Air Combat Command Intelligence Directorate, 1A8XX Air Force Specialty manager, cut the ribbon during the POW/MIA 24-hour Recognition Run opening ceremony at Joint Base Langley-Eustis, Virginia, Sept. 21, 2018. The United States’ National POW/MIA Recognition Day is observed across the nation on the third Friday of September each year. (U.S. Air Force photo by Airman 1st Class Anthony Nin Leclerec)

U.S. Air Force Retired William “Blister” Townsley leads the first two laps during the POW/MIA 24-hour Recognition Run opening ceremony at Joint Base Langley-Eustis, Virginia, Sept. 21, 2018. Townsley spoke about being shot down while flying a Cessna O-2B Super Skymaster during the Vietnam War. (U.S. Air Force photo by Airman 1st Class Anthony Nin Leclerec)

U.S. Air Force Airmen assigned to the Langley Air Force Base Honor Guard post the colors during the POW/MIA 24-hour Recognition Run closing ceremony at Joint Base Langley-Eustis, Virginia, Sept. 21, 2018. The United States’ National POW/MIA Recognition Day is observed across the nation on the third Friday of September each year. (U.S. Air Force photo by Airman 1st Class Anthony Nin Leclerec)

U.S. Air Force Airmen from the Air Force Sergeants Association Raptor Chapter 358 finish the POW/MIA 24-hour Recognition Run at the POW/MIA Memorial on Joint Base Langley-Eustis, Virginia, Sept. 21, 2018. The POW/MIA flag was raised at Langley Air Force Base’s POW/MIA Memorial Park, following the 24-hour recognition run. (U.S. Air Force photo by Airman 1st Class Anthony Nin Leclerec)

U.S. Air Force Master Sgt. Sharon Nichols, Air Combat Command Directorate of Air and Space Operations command and control operations manager, and Senior Master Sgt. Vanessa Johnston, ACC Intelligence Directorate, 1A8XX Air Force Specialty Manager, raise the POW/MIA flag during the POW/MIA 24-hour Recognition Run closing ceremony at Joint Base Langley-Eustis, Virginia, Sept. 21, 2018. The flag was kept in movement by Airmen across Langley Air Force Base for 24 hours as part of the POW/MIA events on base. (U.S. Air Force photo by Airman 1st Class Anthony Nin Leclerec)

U.S. service members attend the POW/MIA 24-hour Recognition Run closing ceremony at Memorial Park on Joint Base Langley-Eustis, Virginia, Sept. 21, 2018. As of Aug. 29, 2018, the number of Americans missing and unaccounted for from the Vietnam War is 1,594. (U.S. Air Force photo by Airman 1st Class Anthony Nin Leclerec)