Military aviation first began as either army or naval aviation units established as force multipliers to allow armies and navies to better do what they were already doing, this taking mostly the form of reconnaissance and artillery spotting, this led to the first fighter aircraft whose purpose was to shoot down enemy reconnaissance and artillery spotting aircraft, and to protect one's own aircraft from being shot down. At this point the purpose of aircraft was still to act as an adjunct to traditional armies and fleets operating in the traditional way. However, as aircraft became more technologically sophisticated military theorists of the interwar period began to think of airpower as a means in and of itself where the critical blow could be delivered by strategic bombing, and the experience of World War II confirmed this.