America can do a much better job than Israel can of taking out Iran's nuclear facilities and striking related Iranian military and political assets to blunt any Iranian counter-strike against us or our allies in the region.
My assumption has been based on Israel taking one main shot at Iran. Missiles might carry out follow-up strikes, but no aircraft would be used.
But why do I assume this? Israel is certainly capable of carrying out a campaign against targets within easy range--in Gaza and southern Hezbollah-controlled Lebanon fairly recently, for example. Just because Israel's strikes on nuclear facilities in Iraq (1981) and Syria (2007) were single mission package strikes doesn't mean that is all Israel is capable of doing.
If either Turkey or Saudi Arabia are fully on board and willing to take the hits in Moslem world public relations in order to facilitate Israeli strikes (even if just by looking the other way and denying Israeli aircraft are flying over their territory), Israel could launch multiple waves of aircraft against Iran.
Now, Israel still can't do as good a job as America even if Israel launches more than one wave of air strikes. And there is no way that Israel would waste strike missions on non-nuclear or missile targets to muffle an Iranian counter-attack in the region, so again American capabilities are superior.
But questioning my assumption about the necessity of a single Israeli strike does put the whole question in a different light.
A lot might depend on Israeli refueling capabilities--either aerial or at a temporary ground location in either Turkey or Saudi Arabia on a nice long stretch of highway closed off to traffic for a couple days.