Ukrainians shot about 30 Russian planes, so 30 experienced Russian pilots are gone This is exactly the metric. Unlike their other assets, planes are expensive

Ukrainians shot about 30 Russian planes, so 30 experienced Russian pilots are gone This is exactly the metric. Unlike their other assets, planes are expensive to replace and pilots take a long time to train. Russia needs to maintain their air assets in order to defend themselves in case they get challenged that way. And they have tons of warm bodies and old hardware to throw at the situation. Another perspective is that Russian air assets are very vulnerable to MANPADS style air-defense systems. Ukraine has received a ton of these systems from the west and are able to engage targets up to about 3 miles out. They're also vulnerable to the S300 systems the Ukrainians inherited, although its not clear how many of those remain.