The Atlantic Alliance was formed on 4 April 1949 in response to the threat of Communism, and it was in this troubled context that the Belgian Air Force was reconstituted. The demand for personnel and equipment was high because east–west tensions required increased vigilance in NATO airspace. The fear of a new world conflict, caused by the Berlin Crisis and especially by the Korean War that broke out in 1950, further reinforced the need for pilots. In 1948, Belgium - like other member countries of the Atlantic Alliance - signed a military cooperation agreement with the United States. In the same year, the United States signed a military cooperation agreement with Belgium. The Mutual Defense Assistance Act covered not only the delivery of military equipment, especially aircraft, but also personnel training. Thus, as early as 1951, the first Belgian students went to the United States to be trained as pilots.