British Caledonian in the 1970s 31 March 1973 - with the BR airline designator it had inherited from BUA at the time of its formation. This resulted in exclusive use of the BR designator as a prefix for all BCal flight numbers. In 1973, BCal also inaugurated its fourth scheduled domestic trunk route between London Gatwick and Manchester. The new service was contracted to British Island Airways (BIA), BUIA's successor, which operated two daily return trips using its Handley Page Dart Herald turboprops. On 20 March 1974, BCal switched its Gatwick—Paris services to the then brand-new Charles de Gaulle Airport in the northern Paris suburb
Airport handling passenger traffic. One of the earliest such fields was Paris – Le Bourget Airport at Le Bourget, near Paris. The first airport to operate scheduled international commercial services was Hounslow Heath Aerodrome in August 1919, but it was closed and supplanted by Croydon Airport in March 1920. In 1922, the first permanent airport and commercial terminal solely for commercial aviation was opened at Flughafen Devau near what was then Königsberg, East Prussia. The airports of this era used a paved "apron", which permitted night flying as well as landing heavier aircraft. The first lighting used on an airport was