He is best known as a member of Operation Vengeance, the top secret mission to intercept the aircraft carrying Japanese Admiral Isoroku Yamamoto in April 1943.

Intelligence sources had learned that Yamamoto would be flying in a "Betty" bomber on an inspection tour of Japanese bases in the northern Solomon Islands.

[2] In 1991, Barber and Captain Thomas George Lanphier Jr. were officially credited with half a kill each in Yamamoto's bomber after the Air Force reviewed the incident.

– discuss] However, despite numerous appeals, the US Air Force refused to reverse its 1991 ruling giving each pilot half credit for the kill.

Participating in a dangerously long interception flight, First Lieutenant Barber contacted a formation of two enemy bombers escorted by six fighters in a complete surprise approach.

Quickly engaging the enemy, he pressed his tactical advantage and struck fiercely, destroying one Japanese bomber at such close range that fragments from the explosion lodged in the wings of his plane, and shooting down the escorting enemy fighter plane which had been attempting to divert the attack.

His brilliant airmanship and determined fighting spirit throughout a daring and vital mission were in keeping with the highest traditions of the United States Armed Services.

The new bridge, plaque and kiosk honoring Barber were dedicated on August 9, 2003, at Peter Skene Ogden State Scenic Viewpoint.