[6] It relieved orders for overseas service and departed Hicks Field on 23 January 1918, arriving at the Aviation Concentration Depot, Garden City, New York on the 26th.

After being delayed for about a month, the 27th boarded a troop ship and departed from New York Harbor on 26 February, arriving at Liverpool, England on 5 March.

The squadron waited until 17 March before crossing the English Channel and arriving in Le Havre, France on the 18th.

[6] After a train journey in French "Cattle Cars", the squadron arrived at Air Service Headquarters, AEF, at Tours Aerodrome on 20 March.

[6] Remaining at Issoudun until 24 April, the squadron moved up into the "Zone of Advance", or the Western Front, at Epiez Aerodrome.

At Epiz, being near the front lines, the squadron continued with practice formations and an occasional alert when enemy aircraft were seen or rumored to be in the vicinity.

With the addition of the RAF planes, Allied aircraft were concentrated on attacking German infantry formations whenever they tried to make an advance.

During the offensive, the 27th continued escort flights of photo-reconnaissance planes so headquarters would be able to know the locations and strength of the enemy forces.

The American offensive began on 12 September after an intense artillery barrage, and the 27th was ordered to conduct close air support for the infantry and machine-gun enemy infantry on the ground; protect observation aircraft and take the offensive to enemy pursuit planes spotted in the sector.

[6] However, on account of weather conditions, flights were limited to about 200 meters in altitude, with patrols primarily supporting the infantry advance and to attack enemy convoys and troop concentrations in its rear areas.

Operations orders received stated that all available aircraft would leave the ground before dawn to attack and destroy all enemy observation balloons.

[6] The 27th successfully brought down four enemy balloons, and an advance flight also moved forward to an airdrome west of Verdun.

On 5 December 1918 orders were received from First Army for the squadron to report to the 1st Air Depot, Colombey-les-Belles Airdrome to turn in all of its supplies and equipment and was relieved from duty with the AEF.

[8] Personnel at Colombey were subsequently assigned to the commanding general, services of supply, and ordered to report to one of several staging camps in France.

There, personnel awaited scheduling to report to one of the Base Ports in France for transport to the United States and subsequent demobilization.

[9] On 2 February 1919, the 27th was moved to Base Station #5 near the port of Brest prior to its return to the United States.

DSC: Distinguished Service Cross; SSC: Silver Star Citation; KIA: Killed in Action; MIA: Missing in Action; POW: Prisoner of War[12] This article incorporates public domain material from the Air Force Historical Research Agency