All the reporting is that Israel has at least 8-10 Boeing 707 based large aerial refueling aircraft, the actual attack aircraft would be about 125 very advanced long range configured F-15L and F-16Ls as well as long range UAVs they have developed on their own. Of course, modern air warfare does not require that individual attack aircraft fly the entire distance using only the fuel they have at take off. They would take off and refuel inflight and probably numerous times inbound and again outbound.

It has been reported that Israel also has planned possible attacks from non-Israeli territory within much closer striking distance, and any attack would likely include a combination of attack modes. Aerial refueling aircraft would possibly be originating from non-Israeli territories, and intercept attack aircraft at various points.

Other strategies could have the attack originating from Israel and then post attack fly-on's to non-Israeli staging areas, in places like Azerbaijan.
A BBC report a couple of hours ago details some of the background on this.

BBC News - Why Azerbaijan is closer to Israel than Iran

Here's a good report from earlier in the year the BBC did about some of the complexities involved.

BBC News - Analysis: How Israel might strike at Iran