Ukrainian pilots are reportedly in Poland picking up MiG-29 fighters and Su-25 ground-attack aircraft; a total of 70 planes. The Su-25 (NATO reporting name "Frogfoot") is broadly equivalent to the A-10 in its role, close in air support and anti-armor ("tank busting").
This is a major step past Javelins and Stingers. The report comes from Politico, who was informed by Ukrainian diplomatic sources, so take that as you will.
Alternative take: this doesn't pass the smell test, according to Joseph Trevithick at TheDrive.
The initial reports seem total bogus to me.
These airframes are NOT something you can just hop into and fly away. They need a ton of support and logistics. The plane and the pilot are the easy part.
My guess is only a few, like 3 or 4, will make it into combat in the Ukraine. And that will take at least a week, if not 3 weeks.