From 1943 to 1947 the Swedish airline Svensk Intercontinental Lufttrafik AB (SILA- Swedish Intercontinental Air Traffic Ltd.) had the unique distinction of operating the only Boeing B-17 Flying Fortresses to be used as airliners. When SILA was established in 1943 for the purpose of developing international air routes, negotiations had been dragging along for airliners from either Great Britain or the United States. On 24 July 1943 the first of an eventual 69 USAAF B-17 bombers landed in Sweden, usually due to battle damage on missions over occupied Europe.
As the numbers of bombers increased, negotiations began with the United States to legally transfer some of these aircraft for use as airliners. With the assistance of the American air attache in Stockholm, Felix Hardison, ten B-17s with spares were transferred to the Swedish government and Saab began a conversion program to transform the B-17 into an airliner.
All military equipment was removed from the aircraft with the nose section lengthened to be used as a cargo compartment. The bomb bay was also converted into a cargo bay and in the aft fuselage two passenger cabins were installed with sound proofing and amenities suitable for long distance passenger transport. Six seats were in the first cabin and eight seats were in the rearmost cabin with the lavatory sharing space with the retraction gear of the tailwheel. The conversion took five months and in Swedish service the converted bombers were designated F17 in honor of the US air attache, Felix Hardison.
No SILA F17s were lost during the Second World War, though one did crash after the war in December 1945. Two of the seven aircraft converted were transferred to Danish Airlines, and one of those aircraft operated with the Danish Air Force as a survey aircraft over Greenland. That particular F17 was restored back to its original configuration as the B-17G "Shoo Shoo Baby" and is on display at the National Museum of the USAF in Dayton, Ohio.
Source: Aeroplane Monthly, November 2009. "From Bombs to Ball-Bearings" by Jan Forsgren, p14-17.