came from American aircraft. Impact and legacy Operation Deny Flight lasted for 983 days and included 100,420 sorties carried out by 4,500 personnel from 12 NATO countries. It included the first combat engagement in NATO history, the Banja Luka incident, and many of NATO's first out of area operations. As such, Deny Flight "represented a momentous act, if only in symbolic terms, in that the alliance assumed a combat mission in a nondefensive capacity and out-of-area". Beyond this symbolic effect, Deny Flight had important consequences for NATO military policy, international relations, and the war in Bosnia. Effect on military policy As one of the first major combat tests of NATO airforces, Deny Flight provided several important military lessons. Most importantly, Deny Flight helped to prove the effectiveness, or drive the development of several technologies. For example, during the operation, the F/A-18D Hornet was proven to be a "highly resourceful multirole platform" for the United States Marine Corps. Deny Flight was also important in the move towards precision-guided munitions, as nearly 70% of the munitions dropped by NATO during the conflict were precision-guided, versus only 8% during the Gulf War. For the Royal Navy, Deny Flight led to a re-evaluation of the Sea Harrier and a number of upgrades to it. In particular, the Royal Navy added the Paveway II laser-guided bomb to the Harrier, giving it a precision capability, and upgraded electronics aboard the aircraft in response to the necessities of combat in Bosnia. The lessons of Bosnia also led the Royal Air Force to deploy the Harrier GR7 aboard Royal Navy carriers for future operations in order to deliver more offensive force projection capability. The four NATO aircraft shot down during Operation Deny Flight also forced NATO members to consider new defensive measures for their aircraft, including increased stealth capabilities. Deny Flight also demonstrated the necessity of better communications and integration among forces operating together, and led to some calls for technical training of UN personnel to work with NATO military systems. Finally, the rules of engagement established under Deny Flight also played an important role in shaping the rules of engagement for later NATO operations other than war, including Operation Joint Endeavor, and even NATO operations in Afghanistan. Effect on the Atlantic relationship Operation Deny Flight, and other NATO operations during the Bosnian War, resulted in significant tension within NATO and the Atlantic relationship. Deny Flight and other