When the Allies invaded Normandy on D-Day, Royal Air Force Airfield Construction Service engineers were among those in the initial assault waves.

They were designed for casualty evacuation and supply transport and consisted of a quickly built runway manned only by a small complement of station personnel with little or no infrastructure other than tents.

Once the combat units moved up to the next assigned ALG, they could be utilised as S&E Fields, or deconstructed quickly and abandoned, with the land being released back to the landowners or civil authorities in the area.

The mission for constructing ALGs was placed in the hands of the Airfield Construction Service of the RAF Second Tactical Air Force, whilst the USAAF's Ninth Air Force and its specially created engineering arm, the IX Engineer Command, were responsible for ALG's in the US sector of operations.

Each aviation engineer battalion in the command (of a total of sixteen) was composed of sufficient men and equipment to quickly construct an airfield or landing ground for a single tactical fighter or bomb group unit.

[1] Captured airfields could be restored for use as advanced landing field in one to three days depending upon the amount of damage and the number of mines and booby traps encountered.

[1] Dry-weather advanced landing fields were constructed by a single battalion at a favourable site in flat terrain in one to three days, including time for reconnaissance.

At less favourable sites, where more clearing and grading were required, or all-weather fields which also needed additional infrastructure, the time varied from three to ten days.

[1] Instead of using rough, unimproved dirt strips, engineers used surfacing material necessary to strengthen the soil to support the weight of the aircraft and as a measure of insurance against the wet weather.

The surfacing material selected for the building of advanced landing grounds during the first weeks after the Normandy invasion was known as square-mesh track (SMT).

It was chosen over other surfacing materials because it was very lightweight, allowing sufficient quantities to be transported across the English channel on over-tasked landing craft.

To provide an all season durable airfield for the RAF's 2TAF and the USAF Ninth Air Force's medium and light bombers, a third type of surfacing material known as pierced steel plank (PSP), or Marsden Matting was introduced on the Normandy bridgehead in July 1944.

These were: Consisted of a rough, graded runway approximately 2000 feet long to provide a place for emergency belly-landings of damaged aircraft.

[3][page needed] A number of ALGs were expanded into tactical air depots by the addition of hangars, shops, more dispersal hardstands, roads, and other facilities.

[3][page needed] Four main designations were given to ALGs on the European Continent: An unforeseen development was the extraordinary demand for transport, supply, and evacuation fields as the Allied armies pushed past Paris toward the German frontier.

In Southern France, another twenty or so fields had been built by American engineers from Twelfth Air Force from the Mediterranean Theater of Operations (MTO).

[1] The stabilisation of the front lines in the Netherlands, Belgium, and eastern France in mid-September 1944, which would last into the new year, allowed aviation engineers a chance to reorganise and prepare for the upcoming winter season.

But sufficient fighter-bomber and medium bomber airfields were completed that winter to ensure 2TAF and Ninth Air Force aircraft could continue flying combat missions.

[1] The renewed allied offensive in early 1945, following the Battle of the Bulge, was supported in earnest by the building of tactical airfields in occupied Germany.

When a crossing over the Rhine River was spearheaded at Remagen, Germany, a supply and evacuation strip was quickly set up to support the bridgehead.

The relative lack of German military opposition in late March, April and May 1945 lessened the need for close air support and produced a greater demand for supply airstrips to keep the offensive moving.

Every opportunity was used to clear captured German airfields for use along the armies' route, allowing C-47s and other transports to land with food, gas, and ammunition.

Throughout Western Europe, as well as the airfields built by Twelfth and Fifteenth Air Forces in the MTO, a significant number were developed into permanent, civilian airports or NATO military bases after the war.

The first being a requirement by the allies to station short-range fighters close to the English Channel coast so missions could be undertaken to attack enemy coastal fortifications; road and rail networks and other military targets in Occupied France prior to the invasion of Normandy.