Beginning in mid-to-late 1944, after the Allies landed in Normandy and began to move east into central France, Darmstadt-Griesheim came into the effective range of USAAF Ninth Air Force B-26 Marauder medium bombers and P-47 Thunderbolts.
The USAAF 410th Bombardment Group trained at the airfield with Douglas A-20 Havocs in the fall of 1943 before being reassigned to the Ninth Air Force in England, where they flew Martin B-26 Marauders.
It was designed by the Glenn L. Martin Company as the Martin Model 190 and was a high-altitude derivative of the company's B-26 Marauder.
In November 1942 Gerrity was assigned to the Army Air Forces Materiel Command at Wright Field, Dayton, Ohio, as project officer on B-25, B-26, B-29, B-32, YB-35 and B-36 bombardment aircraft.
Although originally designated to produce the Martin B-26 Marauder medium bomber, the Malton plant received a contract on 18 September 1941 to build the Avro Lancaster Mk X heavy bomber.