Yeah I kinda hope/suspect that training and procurement has actually been going on sooner than they say. Might be wishful thinking, but it would be awesome if F16s show up on the battlefield early and catch the Russians totally off guard
And is unlikely to be achieved by 42 f16s. Don't get me wrong, this is fantastic news, but it would take many many more f16s and/or more sophisticated jets and more air defenses to establish air superiority.
I haven't seen much discussion about it, but I think F15s for Ukraine would be incredibly helpful. F15s have a very powerful radar with excellent standoff and air-to-ground capabilities. I think they would go a loooong way to keeping Russian jets behind their air defenses, and slowly picking off those air defenses.
Hopefully this is the same as the Challenger tanks given by the UK. In itself it'll make little difference, but enabled other countries to supply their own tanks.