As with all CGI of WW2 aeroplanes, the speeds they fly at look completely wrong. The ME109s flashing through the B17 formations appear to be going at phenomenal speeds, way in excess of the 350 - 400mph they were probably doing. If you look at actual footage from these battles, the German fighters are going nowhere near the speeds portrayed by CGI. I assume that they're all speeded up to add to the excitement, but it just looks wrong to me.