Yes, I know this isn't an airplane model forum but...

How is airplane flight possible or not in heavy rain or snow, or extreme cold? I could not help but wonder if Russian winters were too much for either side's air forces.

Well, the physics are the same; Lift vs. Weight, Thrust vs. Drag. Just EVERYTHING gets harder in cold weather. Getting fuels and lubricants to flow is a major challenge. Banging your knuckles against cold engine bits hurts twice as much. cleaning snow and ice off of the plane is a chore and keeping ice from forming on the plane is a nightmare.

There was the 'reality' series about Buffalo Airlines flying DC-3's and C-46's up in Canada. They had heaters that they'd wrap around the engines to get them warm enough to turn over. Nothing was easy, they even had to get special heaters to warm up the turbos on their P-3 before they could get the plane started.