Just before the belly landing at about 50:00, the inside starboard engine is not running. Several seconds later in subsequent shots, all engines are running.
When the SS interrogate the farm girl, the officer is wearing a black overcoat with swastika armband, yet in the next scene he is seen wearing a combat uniform.
The German soldiers are supposedly SS troops but wear the Wehrmacht eagle on their uniforms and on the officers forage cap. Also, at least one soldier is seen wearing the GD cipher on their epaulets of the Grossdeutschland Division which never served on the Western Front, only the Eastern Front.
Also the number plate on the Kubelwagon displays a number plate with incorrect lettering.
Engines on the B-24 Liberators are all shown turning to the left. While it is correct that all four of the Liberator's engines turned in the same direction, that was to the right [Pilot Training Manual For The Liberator; AAF Manual No. 50-12, p.69]. The work in progress 3D model seen in the Bluray's bonus feature "VFX Breakdown" shows props turning in the correct direction.
The pilots mention trying to make it to Falaise which is in France, nowhere near their location in Germany. Allied troops didn't make it onto German soil until 1945 in the month of March.
RAF personnel never saluted if they were bare headed.
When Capt. Kirk was discussing the upcoming mission under the wing of his B-24 Liberator aircraft, a modern VOR antenna was seen on the fuselage. The aircraft must be a still-flying example of this great aircraft, but this equipment was not invented until in the late 1950's.
On several occasions they use the American pronunciation LOO-tenant for lieutenant rather than the British LEFT-tenant.
It is doubtful that in 1944 a British pub would have big posters for Coca Cola and Pepsi Cola.
Film is set with RAF flown Liberators based in Britain, attacking Bremen in Germany. Liberators are American aircraft, flown & operated by RAF crew 99% in the Middle East, in Asia against the Japanese, and Egypt & Italy against the German forces.