In July 1940, the Battle of Britain began. This was the name given to the German military operation aimed at conquering the airspace over southern England. According to the German command, this was to undermine the morale of the British people. To protect the airspace over large cities, the British used barrage balloons with taut cables. To break through the barriers, the Luftwaffe used converted airplanes on which special steel structures with cutters were installed. The cutters were also called paravans, similar to devices for protecting against sea mines. Among the converted aircraft were He 111 bombers, this modification was designated He 111H-8. Piloting such aircraft was quite difficult, as the massive structure of the paravan worsened the flight characteristics of the aircraft. Some of the see aircraft were lost during 1941, and the remaining ones were later used as conventional bombers.