During December 1944 a number of significant events had occured in the preparation for the invasion of north-west Europe. On 4 December, Operation Crossbow had been launched, aimed at the destruction of rocket and flying bomb sites. The V-weapons were seen as an immediate threat to the massed Allied forces that were building up in the south of England. By 19 December, 54 sites had been identified as operational or under construction and attacks were being carried out by RAF and USAF aircraft. In a Christmas Eve broadcast, President Roosevelt had announced that General Dwight D Eisenhower had been appointed as supreme commander of the Allied Expeditionary Force already assembling in Britain. In London, on 27 December, Air Chief Marshal Sir Arthur Tedder was appointed deputy supreme commander. The main pieces were in place, and operations to defend the forces had begun. The stage was set.
1 January - The US Strategic Air Forces in Europe Command was formed, covering all the US Army Air Forces in Britain. General Carl Spaatz was named as the commander. This command would be responsible for continuing the strategic campaign against German industry as well as the tactical considerations of support for D-day.
4 January - Operation Carpetbagger begins. Aircraft are diverted from the strategic bombing campaign to fulfil the requirements of the Belgian, Dutch, French and Italian resistance for weapons and training specialists. In the week beginning 9 January, enough weapons to equip 20,000 resistance fighters were dropped. The resistance would play a vital role in disrupting German communications and transport in the build-up to the invasion.
6 January - The D-day timetable is delayed until the end of May after General Montgomery revises the original plans. The first Anglo-US plans called for only three divisions to be landed initially, because of the shortage of landing craft. Their flanks would be protected by two divisions of airborne forces and rapid reinforcement would land a total of 18 divisions once the beach-head had been secured. Montgomery considered that the three division plan would present the Germans with a simple containment situation, and with the congestion caused by the rapid reinforcement plan, the possibility of failure was too high. Eisenhower agreed with Montgomery's recommendations and a new plan emerged. Five divisions would be landed on a 50 mile front from the River Orne to the Cherbourg Peninsula. An additional airborne division would also be added to the flank protection plan. A much larger number of landing craft would be required, hence the delay until May.
11 January - This day marked the beginning of the air operations designed to support the Allied invasion of France (Operation Overlord).
27 January - Churchill reinforces the invasion tasking of Allied air power by stating two priorities for Bomber Command operations in his directives. The first was to bomb targets on the continent, the second was to supply the resistance with arms.