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 Eighth Army Air Force which carried out the strategic daylight bombing campaign against the Third Reich.

If you were to ask about the symbolic aircraft of the desperate defence of Polish sky during the tragic September '39, without any doubt the answer should be one - the PZL P.11c. Although older machines (PZL P.7a and P.11a) fought next to it, the mentioned variant was a true backbone of the defence force. Pilots liked P.11c but in all publications it is described by an adjective "obsolete". It was the penultimate stage in the evolution of a long line of fighter planes, no longer having the disadvantages of the "infant period", but also actually constituting a closed alley in the evolution of this type of design. The PZL P.11g modification showed that the already mature construction can only be improved to a small extent. Being an export alternative, faster, equipped with a much more powerful engine and better armed PZL P.24 were actually the end of the possibilities of high wing strut aircraft. This was understood in Poland, where design offices were no longer involved in the further development of such structures (P.11g was just an emergency attempt to obtain not the most modern, but an efficient fighter). Unfortunately, it was not possible to produce or buy a successor abroad on time. That is why Poland entered the conflict equipped with fighter planes, once belonging to the world leaders, but giving way to the latest enemy machines.