that during the first four decades of NATO's existence the Alliance carried out no military operations?
During the Cold War NATO's priorities lay with ensuring an effective defence of the Alliance's territory so as to deter any potential attacker.
Thus NATO concentrated on drawing up effective defensive plans, building up the necessary military forces, raising the standards of their proficiency and ensuring effective multinational cooperation through a wide range of military exercises.
NATO was thus very active from 1949 to 1989, but the focus was on plans, procurement, training and multinational exercises within the NATO area. It was not until the end of the Cold War that NATO began conducting actual military operations, beginning with defensive measures taken to protect Turkey against an attack by Iraq during the first Gulf Crisis and War in 1990-1991.