 On 5 September 1944, American P-51 Mustangs escorting a damaged B-17 bomber crossed into Swiss airspace and were confronted by Swiss Messerschmitt Bf 109s.Not realizing they were over Switzerland, the P-51s attacked the Swiss Messerschmitts, shooting down one and killing its pilot, and damaging another one.American and British planes bombed Switzerland about seventy times during World War II, killing 84 people.