The air force was probably the most vulnerable to corruption, pilots only got an hour a month of flight time, barely enough to be proficient, God knows if they have decent simulators, or many. They sell their jet fighters abroad, and that can generate a black market for spares and such. They sell fuel on the black market, which is why they don't fly much and maintenance takes spares that have been sold off. Like tanks I imagine some planes in storage or reserves have been stripped of vital parts over time, maintenance is a much bigger issue in air forces than armies.
My guess for the air force no show was chronic corruption eroded their war fighting ability. They must have known at some level how bad it was and every body put their best foot forward for the invasion to impress Vlad and hope it went off without a hitch. So I figure the rest of Vlad's military is worse than what he sent to Ukraine or about the same. It was in effect a massive audit, a very large statistical sample of his forces that shows what he really has in the cupboard, not much.