Second Lieutenant Hummer was the pilot of a F-86F Sabrejet fighter bomber with the 80th Fighter Bomber Squadron, 8th Fighter Bomber Group. On 16 June 1953, while on a combat mission, his aircraft failed to pull out of a bomb run, crashed and exploded. He was listed as Missing in Action while participating in aerial support over Korea on 21 April 1954. He was presumed dead on 21 April 1954. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Hummer was awarded the Air Medal, the Purple Heart, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.