Leiston's location only three miles from the North Sea Coast made it ideal as a Fighter Group air base whose job would be to escort bombers across the sea and over occupied Europe. The air base also witnessed the arrival of many very damaged Allied aircraft who were just grateful to make landfall in Britain. The 358th Fighter Group were replaced by the 357th Fighter Group early in 1944, flying P-51 Mustangs rather than P-47 Thunderbolts. These Mustangs were able to fly greater distances in escorting bombers to eastern German targets like sites in Berlin and Leipzig.