In any competition - most of all, war - the worst mistake one can make is to underestimate one's opponent. It's also the most common mistake.

We in the US Navy have submarine-launched ballistic missiles, cruise missiles, and close-in weapons systems (CIWS) for defense against cruise missiles. We copied (or stole) all those from the Soviets. The original concept and base mathematical proof for stealth tech was done by a Soviet scientist. We saw it and developed it for real-world use. Sloped armor for tanks was a Soviet idea. So were RPG's. So are supercavitating torpedoes (which, as a retired Navy engineer, scared me then and now).

In other words, we Americans are great at copying or stealing ideas from others. From the Nazis we kickstarted our own rocket industry from Werner Von Braun, the designer of the V-2. The Brits developed radar, sonar, and tanks. Churchill himself was the progenitor of the LST - 'landing ship, tank', and his support of tank production made a big difference in the last year of WWI. The examples are legion.

So...yeah, it's entirely possible that the Soviets had a more advanced aeronautics program. That doesn't mean they're ahead in everything or even in a majority of techs. It's almost as if it falls into a pattern of somebody has an idea, we steal it or copy it and develop it for real-world use or improve it.