A helicopter was used in 1944 in a search and rescue operation on the St. Lawrence River . An American Sikorsky R-4 was dispatched for the search , but the survivors were recovered by icebreaker . In 1945 , another US R-4 was sent to transport survivors of a Canso crash in Labrador . US Coast Guard helicopters were again called for rescue service in September 1946 , to recover the survivors of a crashed Sabena DC-4 that had impacted 30 miles southwest of the Gander airport . The RCAF acquired its first helicopter , a Sikorsky S-51 , in 1947 . Further helicopters were acquired by the RCAF and RCN and used for search and rescue . Many flights were carried out during the 1950 Red River flood for passengers and air photography . In 1955 , helicopters of the RCAF No. 108 squadron were used in support of construction of the Mid Canada Line of radar stations . During the 1950s and 1960s , United States defence planning viewed Soviet aircraft travelling over the Arctic as a threat , and expended much effort and money on defensive systems . Early-warning radar stations of the DEW line and Pinetree Line constructed partly within the Canadian North ; construction of these stations required many air freight shipments in isolated areas . Additionally , anti-aircraft missiles called BOMARC were also stationed in Canada . These were highly controversial since they had the capability of carrying a nuclear bomb
1950 Red River flood
1950 Red River flood
History of aviation in Canada