'Where and When' was a US clandestine air transport operation to and from neutral Sweden to occupied Norway during the closing stages of World War II (22 December 1944/August 1945).

From 1943, as the balance in World War II swung decisively toward the Allies, Sweden started to consider and implement ways of supporting them without jeopardising the country’s technical neutrality, and even went so fat as to establish a training camp for Danish and Norwegian 'police troops', who were in fact volunteer army units intended, among other things, to assume the responsibility for security in those parts of their homelands which German troops evacuated. As part of this Swedish semi-commitment to the Allies, from the spring of 1944 US courier flights were permitted as 'Sonnie' between Bromma airport outside Stockholm and Leuchars near Dundee in Scotland. These flights were organised by the US Office of Strategic Services in partnership with US Army Air Forces' Air Transport Command. The undertaking was supervised by the Norwegian-US pioneer polar aviator Colonel Bernt Balchen, and was intended to fly Norwegian resistance fighters and recovered Allied air crews to England.

Allied secret military organisations, such as the Norwegian XU and Special Forces Headquarters in London, and including the British Special Operations Executive and US OSS, also began to the process of creating some 30 bases in the mountains along the border between Sweden and Norway, about one-third of them in Sweden, in 'Sepals'. These 'Sepals' bases were established in co-operation with Swedish military intelligence.

In the spring of 1944, Balchen was authorised to start negotiations with the Swedish authorities for the use of a Swedish base for the operation of US aircraft directly to areas in northern Norway. When the Soviets launched their 'Petsamo-Kirkenes Strategic Offensive Operation' in the Arctic on 7 October 1944 and quickly approached Norwegian territory, the US air transport effort through Sweden gained considerable impetus.

On 29 October there was a meeting between the Norwegian government-in-exile’s foreign minister, Trygve Lie, and the Swedish prime minister, Per Albin Hansson, in the course of which the former conveyed a request from the Western Allies to gain approval for the insertion of Norwegian police troops into the Norwegian town of Kirlenes, which had been liberated four days earlier, using US aircraft wearing US military markings and carrying personnel in US uniform would be used. This resulted rom the appreciation of all the parties involved that the occupants of any aircraft brought down in German-held territory would not benefit from the laws of war.

Sweden responded positively to most of the Allied requests in November. The operation’s Swedish terminus was to be the F21 base at Luleå, but uniformed Americans were not to leave the base and no US warplanes were to be based in Sweden. After further negotiations between Sweden, USA, UK, USSR and Norwegian government-in-exile, agreement was reached on 15 December that the Soviets would permit operations to and from bases in northern Norway after each of them had been specifically authorised by the Soviets to the Swedish air force.

Meanwhile, the 10 Douglas C-47 Dakota transport aircraft flown by crews of the 27^th Air Transportation Group constituted the US Strategic Air Forces in Europe’s Luleå Detachment. The commander of 10 aircraft and 50 personnel was Captain Charles Holliman, under the supervision of Balchen as the head of the whole 'Where and When' operation.

The British end of the undertaking was located at Metfield in England, and it was from there that the first flight was launched late in the evening of 22 December. The aircraft were engaged by German anti-aircraft fire over Norway, where one of the aircraft had to turn back, and the others landed at Bromma airport during the morning of 23 December. After a delay of a few days as the required permits were issued, the aircraft flew via the F1 base at Västerås, where a complete field hospital and 14 tons of equipment were loaded, to the F21 base in Luleå, where they touched down on 30 December.

Barracks had been hastily built at the F21 base for the US aircrews and technical personnel, totalling more than 100 persons, and the Norwegian police troops. It was on 29 December that the latter started to arrive at Luleå by railway, and were billeted at the F21 base next to the Swedish conscripts.

On 7 January 1945 the headquarters of the Soviet forces on the Kola peninsula sent at radio message to the F21 base that it had received the codes from Moscow which would enable communication with the Swedes, and thus co-operation. Then the flight programme was delayed by adverse weather to 12 January, when all 10 aircraft flew to Høybuktmoen, the German-built airfield about 9.25 miles (15 km) from Kirkenes, where the field hospital and other equipment were unloaded with the help of the Americans, Norwegian police troops and Soviet troops. One of the aircraft had almost been shot down over Finland by a Junkers Ju 88 of the Finnish air force, whose crew had not given information about the overflights. The routes from Luleå to Norway passed over Kemi airfield, the main base for the Finnish air forces involved in the 'Lapinsota' offensive designed to expel the German forces Finnish Lapland.

As noted above, the original purpose of the operation was to deliver Norwegian police troops and while flights were made primarily to Kirkenes, some deliveries were also made to Bodø, Karasjok and Kautokeino. The operation was also used for the alleviation of humanitarian problems in what had been German-occupied northern Norway, and to aid the Norwegians in persuading the Soviets that they should not remain in northern Norway after expelling the Germans. The operation was also a support for the 'Sepals' bases in the Swedish/Norwegian mountains.

When 'Where and When' was completed in August 1945, about 1,550 personnel and 360 tons of matériel had been delivered by air from the F21 base to northern Norway in a total of 572 sorties.