Ukrainians are 100% sure they'll get the F-16s. In fact Ukraine Ministry of Defense advisor Yuriy Sak said, that short of nuclear weapons they can get 'em all. It's fun they gave up their nuclear weapons which could have ensured the "sanctity" of their borders, in exchange for NATO's insurances.
Anyway Ukrainian officials say interesting stuff.
Yuriy Ignat, spokesman for the Air Force Command of the Armed Forces of Ukraine said they have to change their whole air force to F-16s and have to set up at least 5 air brigades (translated from Hungarian, not sure what would be the proper term, and how Ukraine organizes it's air fleet, maybe they meant wing or division).
Zelenskiy visited EU, he chimed in too (quoted from the English article):
>“This day has become very fruitful and I’m grateful to the Prime Minister for understanding our needs and for his helpful advice.” The President also suggested that Ukrainian pilots could be trained in a matter of months, rather than the three to five years previously claimed by the UK Government.
>in a matter of months
Maybe they operate on the survival of the fittest basis. They set up 5 air brigades in months, and the pilots who stay alive after the first fights are gonna be damn good pilots in a size of a squadron. Or less.

https://inews.co.uk/news/we-havent-got-any-fking-jets-give-doubts-over-how-rishi-sunak-help-ukraine-air-power-2137740
https://index.hu/kulfold/2023/02/09/haboru-oroszorszag-ukrajna-nyugat-vadaszgepek-szallitasa-brit-miniszter-nyilatkozata/
https://index.hu/kulfold/2023/02/01/haboru-orosz-ukran-konfliktus-harci-repulogepek-szallitas-nagy-britannia-litvania-lengyelorszag-egyesult-allamok/