Russian tactical assault aircraft were the best in the world at that time. Their fighters were also quite good. The Red Army dwarfed the Western Allied Armies. Most of their tanks were not super heavy ,but T-34 medium tanks, the best tank in the world in mass use at the time. The only thing we had to compare with that one was the Pershing, and we had very few of those. They had thousands of T-34s. Our artillery was better quality, but they had a hell of a lot more of it, and theirs was very good too. Almost all historians think that war would have been short, and would have resulted in the Soviets on the English Channel. It's something that most Americans don't know, or if they do they won't acknowledge, but the Russians beat the Nazis. That war was decided on the Eastern front. We helped them with supply (trucks were the most important contribution), mostly early on, but they did the fighting and dying. The Germans were already on an irrevocable retreat in the east by the time D-Day happened. What the Western Allies did was to help end the war probably a year or two earlier than it would have otherwise. We also moved the eventual location of the Iron Curtain from the English Channel to Central Europe. That was every bit as important as defeating the Germans. Imagine a Cold War where ALL of Europe is Soviet.