The DAF adapted the "Luftwaffe" concept of tactical air support by using fighter-bombers linked via radio to "Forward air controllers" attached to Army units. The DAF improved the concept by introducing "cab ranks" of fighter-bombers in the air waiting to be called on. The DAF provided air support to the Eighth Army until the end of the war, fighting over Egypt, Libya, Tunisia, Sicily and mainland Italy. The tactical concepts which had proven so successful in the latter part of the North African campaign were adopted with even greater success during the Invasion of Europe in 1944.