Comment by nickff

From looking at the sources below, it looks like Ukraine still has about 1/3 of the fighter aircraft it started the war with, though it started with many non-serviceable units (seems that at least 20 aircraft were non-operational), and received many parts from abroad:

https://en.wikipedia.org/wiki/Aerial_warfare_in_the_Russo-Uk...

https://aerospaceglobalnews.com/news/how-many-aircraft-losse...

I am not sure what is meant by 'a significant number of', and I'm not sure if all commenters have a common definition of that phrase, so I'm unable to judge the veracity of the comments above.