Putin would never have invaded if Trump were still President. And even if he did, Trump would have approved the transfer of the MiGs.
He also would have led the charge for crippling sanctions to 100% cut off Russia’s funding of the war, i.e. a total embargo on oil and gas. The embargo would have been replaced, at no cost to ourselves, by ramping up domestic production.
Trump was already painted a Neo-Nazi by the press and this was despite his supposed “anti-war” rhetoric. If Ukraine was invaded under Trump’s watch (and Trump responded forcefully), the howls of dictator would have been even more deafening than they were. Trump needed a war like he needed more Dem-controlled metropolitan areas in swing states.