While it may be true that American fighter jets like the F-35 and F-15EX are much more expensive than their Russian counterparts, they also have far more flight hours (as well as other advanced capabilities unmatched by Russia). The shorter flight hours of older Soviet and Russian fighter jets is partly why Defense News recently suggested the Russian Air Force fighter jet fleet may have decreased around 25% since the beginning of the Russian invasion of Ukraine (mostly due to wear and tear).