 From 1941 to 1942, Allied bombers very rarely flew over Switzerland, because the Swiss authorities, under German pressure, prescribed black-outs in order to complicate navigation for U.S. and British air crews.As neutral Swiss territory was safe for Allied bombers, Germany also pressured the Swiss into forcing the Allied air crews to land in Switzerland, instead of letting them continue bombing runs.In 1943, the Swiss military began attacking Allied aircraft breaching Swiss airspace.