Operation Sky Monitor was a NATO mission to monitor unauthorized flights in the airspace of Bosnia-Herzegovina during the Bosnian War. The operation began in response to United Nations Security Council Resolution 781, which established a ban on the use of military aircraft in Bosnian airspace, and requested the aid of member states in monitoring compliance. Beginning on October 16, 1992, NATO monitored violations of the no-fly zone using E-3 Sentry NAEW aircraft based in Germany, Italy, Greece, and the United Kingdom. The operation documented more than 500 violations of the no-fly zone by April 1993. In response to this high volume of unauthorized flights, the Security Council passed Resolution 816, which authorized NATO to enforce the no-fly zone, and engage violators. In response, NATO d