Israel will need at least 100 fighter planes to strike Iran, a media report said on Monday.
Israeli forces will also have to fly over 1,000 miles above unfriendly airspace should it decide to attack Iran, the Haaretz daily said citing a report in the New York Times.
According to the Times report, American military analysts and defence officials believe an Israeli strike on Iran's nuclear facilities would be a highly complex operation.
It will be different from Israel's 'surgical' strike on Iraq's Osirak reactor in 1981 and also differ from the strike it is believed to have carried out in Syria in 2007.
"All the pundits who talk about 'Oh, yeah, bomb Iran,' it ain't going to be that easy," the report quoted Lt. Gen. David A. Deptula, who retired last year as the US Air Force's top intelligence official, as saying.
The report also cited comments by former CIA director Michael Hayden, who said that Israel is not capable of carrying out airstrikes that would seriously set back Iran's nuclear program, partly due to the distance the aircraft would have to travel.
According to the report, US military analysts believe that Israel will have a serious problem reaching Iran's four major nuclear sites - the urnainum enrichment facilities at Natanz and Fordo, the heavy water reactor near Arak, and the uranium conversion plant near Isfahan.
Israel has three possible routes to those facilities - north over Turkey, south over Saudi Arabia, or a central route across Jordan and Iraq.
US defence analysts believe that the route over Iraq would be preferable, since Iraq effectively has no air defences and the US is no longer defending Iraq's airspace.
According to officials, should Jordan allow Israel to fly over its territory, the next issue for Israel is that the range of its fighter jets falls short of the 2,000-mile round trip.
For this reason, officials say, Israel would need to use airborne refuellers which would need to be protected by more fighter planes, which significantly increases the number of planes needed for the operation.