‘Stockholm Express’
Between 1943 and the end of the war, Mosquitos were used as transport aircraft on a regular route over the North Sea between Leuchars in Scotland and Stockholm, in then-neutral Sweden.
To ensure that the flights did not violate Sweden's neutrality, the aircraft carried civilian markings and were operated by crews who were nominally "civilian employees" of British 
Overseas Airways Corporation (BOAC). They carried small, high value cargoes such as precision ball bearings and machine-tool steel, as well as Diplomatic Bags. Important 
passengers were also carried in an improvised "cabin" in the bomb bay