[1] In late October 1944, the 825th Engineering Aviation Regiment returned to the airfield and began improvements, laying down an all-weather Pierced Steel Planking (PSP) runway for Ninth Air Force combat fighter use along with upgrading the support site with tents for billeting and also for support facilities; an access road was built to the existing road infrastructure; a dump for supplies, ammunition, and gasoline drums, along with a drinkable water and minimal electrical grid for communications and station lighting.

Three squadrons of P-47 "Thunderbolts" bombed and strafed such targets as flak positions, armored vehicles, and troop concentrations during the Battle of the Bulge.

Despite the intense anti-aircraft fire encountered while flying armed reconnaissance in close cooperation with infantry forces in that area on 16 March 1945, the 362d hit enemy forces, equipment, and facilities, its targets including motor transports, armored vehicles, railroads, railway cars, and gun emplacements.

An agreement was reached to redevelop Etain and to station United States Air Force tactical fighter-bombers there by the end of 1954.

The first USAF unit to use Etan AB was the 388th Fighter-Bomber Wing, deploying to France from Clovis Air Force Base, New Mexico in December 1954.

They provided general engineering services in the area including in Verdun, the old Maginot Line (NATO facilities), and in Etain.

The 249th Engineer Battalion (Construction) also was assigned the base to build a railroad spur line to a munitions dump near the old World War I battlefield.

In late summer of 1965, the 249th relocated back to Germany while the 97th moved to Sidi Brahim Barracks in Étain town proper, freeing up the base for Air Force reserve use during the Berlin Wall crisis.

In addition to these Army units, some small USAF weather, civil engineering and postal squadrons were assigned to the base.

The 121st Tactical Fighter Wing of the Ohio Air National Guard were called to active duty for a period of twelve months on 1 October.

In July 1962 the deployed Air National Guardsmen were no longer needed in Europe and the 7121st began to redeploy its personnel to Ohio.

1 Wing RCAF (Royal Canadian Air Force) from Marville AB used Étain during May 1965 for NATO exercises, but otherwise the base remained largely unoccupied.

On 7 March 1966, French President Charles De Gaulle announced that France would withdraw from NATO's integrated military structure.

By 16 November, all American equipment was removed from the facility and on 15 March 1967 Étain Air Base was returned to the French.