The Battle of Britain Five Months That Changed History, May—October 1940 by James Holland (z-lib.org).epub

because it ran counter to the more methodical approach Halder and the
OKH had already put forward. Halder understood Hitler well enough to
recognize that Manstein’s plan would almost certainly appeal to the
Führer’s go-for-broke mentality. Furthermore, Hitler had even suggested a
thrust through Sedan himself, not through any genius of military thinking,
but rather because Sedan had witnessed the French surrender during the
Franco–Prussian War in 1870 and had always fascinated him.
At the beginning of the year, however, two events happened that turned
Halder’s plans on their head. The first was on 10 January, when a German
aircraft made a forced landing near Mechelen in Belgium. On board was a
Luftwaffe operations officer with copies of the latest German offensive
plans, which still held that a thrust through the Low Countries was to be the
main point of attack. Realizing how important the documents were, the
German officers hastily tried to burn them. They were captured, however,
before the documents had been destroyed. Suddenly, the Allies had the
details of the German plans laid out before them.
Hitler was incensed when he found out, but it soon proved to be of far
greater benefit to the Germans than the Allies. The incident prompted a
rapid response from the Allies, who began enormous troop movements,
going on to the alert all along the front and moving reserves forward, all of
which was watched and noted by Luftwaffe reconnaissance planes. And
what this showed was that the Allies had been expecting a German attack
exactly as outlined in Halder’s plans.
The second event happened a few weeks later on 2 February, when
General Schmundt, Hitler’s military aide, visited Army Group A and was
given copies of von Manstein’s plan by Generals Günther Blumentritt and
Henning von Tresckow. At the end of January, von Manstein had been
sidelined by being given a phantom corps that had yet to be organized.
Frustrated by such treatment of a man they greatly admired, Blumentritt and
von Tresckow urged Schmundt to visit von Manstein and talk to him about
his ideas, which he did right away. He then passed the plans to Hitler. Just
as Halder had suspected, the Führer lapped them up immediately.
But by this time, however, the situation had greatly changed. The long
winter months had proved more beneficial to the Germans than the Allies:
ammunition stocks had been replenished, more tanks and aircraft had been
built, training of raw divisions had been carried out. And spring was around
the corner. The OKH had successfully managed to stall Hitler, their cause