The idea is there.
The easiest way it to ship them into Ukraine and then fly them but shipping planes armt easy.
So they may be working on things under the table bit publicly the deal is done
No, it's really not.
What has to happen is:
1) Poland is willing to lose the planes, and is requiring that the US provide replacements. Which means the US needs to pony up 20+ air frames. This is a non trivial exercise for the US.
2) The planes are stripped of NATO gear. It would actually require laws and/or treaties to be changed to allow the transfer of some of the equipment to a non-NATO member, which means stripping it out and replacing it before the planes are turned over to Ukraine. This takes time, assuming that appropriate parts could be acquired in short order.
3) Get the planes into a state where they can be moved via cargo ship, truck, or rail into Ukraine. Because they aren't going to be flown in. Unless Poland or Romania are willing to play an active and direct role in that transfer, transporting them via ship is the only option. That means flying them, probably, to Turkey and then loading them up on a cargo vessel to transit the Black Sea to Odessa. This is a transfer that will both take a decent amount of time and carry its own substantial risks.
4) Ukraine gets the jets into a combat ready state and starts using them.
---
The idea of transferring fighters to Ukraine was stupid from day one and never should have been brought up. It was never a realistically viable undertaking in a useful time frame.
My guess is we might see a 'Eagle Squadron' of foreign volunteer pilots and ground crew decide to take the planes to Ukraine as 'private citizens' and either stay as part of the pro-Kiev foreign forces, or quickly skeedattle back across the Polish/Ukraine border.
Poland is of the "fuck no" position on that topic. Russia will treat any direct flight of those planes from Polish to Ukrainian territory as Poland actively joining the war in Ukraine.