During World War II, the US Air Force, the USAAF (United States Army Air Force), was not an independent type of armed force and was formally under the command of the army. Thanks to their excellent industrial base and efficient organization, they became the most powerful military aviation in the world during World War II. It is also worth remembering that the USAAF grew tremendously in terms of the number of personnel - in 1939 they numbered about 25,000 people, but at its peak, i.e. in the summer of 1944 - as many as 2,400,000 people! So in five years they have grown almost 100 times! In this number, approx. 300 thousand. were officers, while about 2.1 million were privates and non-commissioned officers, mainly from ground service. Despite such enormous growth, the USAAF implemented effective training systems and methods, which made the overwhelming part of the above-mentioned personnel perform their tasks efficiently. It can also be mentioned that all types of technical and mechanical facilities were used on a large scale in the work of ground handling, which shortened the number of hours needed to bring a given machine to take-off and flight. It is worth remembering that the number of US overseas air bases also increased dramatically, in December 1941 there were 19, and in May 1945 - as many as 130!During World War II, the US Air Force, the USAAF (United States Army Air Force), was not an independent type of armed force and was formally under the command of the army. In the course of this conflict, they became the most powerful military aviation in the world, and at the time of the end of hostilities, they numbered about 2.25 million people! Due to the fact that the American aviation industry was one of the most modern and efficient in the world, the USAAF saw many successful, and sometimes great, aircraft models. It is worth remembering that in 1940-1945 it produced a total of approx. 295 thousand. machines, and therefore more than the aviation industry of Germany, Italy and Japan combined. Moreover, among these thousands of machines produced, one can point to the very successful P-38 Lightning, P-47 Thunderbolt or P-51 Mustang fighters, B-25 Mitchell or B-26 Marauder tactical bombers, but also the legendary B-17 Flying Fortress strategic bombers. and the B-29 Super Fortress. The USAAF pilot training system can also be considered successful and well-thought-out, as it was able to provide the rapidly expanding air force with well-trained pilots. It is also worth remembering that, unlike the German aviation, the American crews and pilots were rotated and after serving a certain period of time, they most often returned to the country, to training units, passing their experiences on. This fact may explain why American fighter aces (such as Richard Bong or Thoma McGuire) had "only" dozens of kills compared to several hundred kills of German aces (such as Erich Hartmann or Gerhard Barkhorn).