The ukrainian pilots are propably training on F16s in secrecy already.

Its just a matter of time, the US is most likely just waiting for the next big russian escalation (start of their new offensive in spring) to acquire the political precedent for announcing the transfer of jets and drones without risking the madman dropping a nuke in response.

Unfortunately the western world cannot risk to enact a significant action like this in an overt proactive way, not when the threat of nuclear escalation is real. All the spy agencies are worried of putin using tactical nukes in response to something like that, given the fact that thats pretty much his last ace up his sleeve now that his army has proven ineffective.