The air echelon left Bruning on 5 September 1943, for Kearns A.A.B., Utah, and on 29 September moved by train to Muroc A.A.B., California, where it would remain until its designated overseas deployment date of 1 December. The ground echelon followed on 8 October. By 1 November, to train approximately 70 crews, the 456th had received only 28 aircraft, all old and half of them grounded for maintenance or lack of spare parts. The shortage of aircraft hampered the training efforts not only of its flying personnel but also its maintenance units.