The North American P-51 Mustang powered by the British-designed
Rolls-Royce Merlin/Packard engine was, quite simply, the best long-range
escort fighter of the World War Two era. Entering service in November
1943, it curtailed prohibitive losses suffered by the heavy bombers of
the US Eight Army Air Force which carried out the strategic daylight
bombing campaign against the Third Reich. In the European Theater of
Operations the USAAF also deployed Mustangs, with great success, as
free-ranging strafers, fighter-bombers, scouts and reconnaissance
aircraft. Eventually, it was the P-51 that broke the backbone of the
Luftwaffe.