Even if all 500 planes are instantly returned at the end of March (how?), there will be reduced traffic to Europe due to the current European bans, and the rest of the traffic will be handled by the remaining fleet. I'm not even talking about Comac or other options.
We'll see in the coming weeks, but the scenario you describe where a catastrophic decline in Russian flights such that there are enough non-Airbus/Boeing planes that can manage them is effectively a collapse in Russian civil aviation sector which is kinda what the thread was implying.
The thread in question https://threadreaderapp.com/thread/1498723248183382020.html
> other critical components
Like what? This sounds a bit hand-wavy, what are those critical components, if you don't mind me asking?
So whom do you have in mind now? Comac?
Since you are so specific, can you at least hint what exactly are these key components that are now being sanctioned? Not engines.
And sure, why not Comac, too, but that's a different story. Doesn't quite look like Cessna, does it?