The second time a genuine Tiger I tank has been used in the production of a WWII film. It features "Tiger 131" from the UK's Bovington Tank Museum, the only fully functioning Tiger I tank in the world.
The cast underwent a rigorous month-long course. The final test was manning a real tank during a combat exercise. Brad Pitt, who was much older than his cast mates, made sure that he participated in all of the physical training alongside the other actors.
About shooting in Oxfordshire, England, Brad Pitt said, "No rations, no showers, and we were sleeping in the rain. It was miserable, but we loved it".
At 50, Brad Pitt, as Wardaddy, is considerably older than the average WWII NCO (non-commissioned officer), who likely would have been in his mid-twenties to early thirties. (David Ayer had originally written the character to be in his late twenties, but looking middle-aged due to the stress of war.) Considering his age, choice of sidearm, and long service record mentioned in the film, it's entirely possible that Wardaddy is a WWI veteran. It would also explain why he knew German before the war started. However, the scene where the tank drives past an entire German town on fire originally ran longer, and had Wardaddy explaining that his mother originally came from a small German town, not unlike the one they are just passing. This would imply he learned German from his mother.