Extra-year? The Soviets may be slowed by the additional resistance in the east, but the measurement will be in additional months... not a year. The German economy was also on track to collapse from overmobilization and resource shortage come mid-1945 irrespective of what was happening on the frontlines in the air, so while the Germans may get some extra-production, their quantities are still going to pale in comparison to what the Red juggernaut can bring to the field. The Germans produced just shy of 1.5 thousand jets, but their manpower and fuel constraints meant they could never operate more then a few hundred of them at any given time. It's really a similar story across the board: overall, German aircraft and tank stocks increased each year. The problem wasn't production, at least not until 1945 when the German economy collapsed in on itself. The problem was sustainability: Germany had neither the trained fuel nor the trained manpower to actually field them, so while the German stockpile of armor and aircraft increased year-by-year, their operational strength continued to dwindle away. Even earlier in the war, 1942-43, the Germans constantly found themselves running fuel shortages of around 30% which wasn't outright crippling, but did impose restrictions of how much they could sustain at any given time. By the Spring of '45, with the loss of the Ploesti oilfields the previous autumn and the synthetic refining plants in Poland during the winter, Germany's last fuel source would be the western synthetic oil plants in the Ruhr. And they just don't have the capacity to pick up the slack. While the Germans may be able to put a few dozen additional jets in the field, against the ten thousand+ late-model piston engine aircraft manned by veteran and ace pilots fielded by the Red Air Force, their a drop in the bucket.