Quote from Misthos:
This topic has already been adressed by the USA. Due to political constraints, sometimes diplomatic channels are unconventional - but the message is just the same.
Zbig Brzezinski: Shoot Down Israeli Planes if They Attack Iran
http://www.israelnationalnews.com/News/News.aspx/133515
Guys like Zbig don't flap their gums for nothing. This was a coordinated realpolitik message IMHO.
Zbig, by the way, crafted Carter's Oil at any cost Middle East Doctrine that continues to this day.
Then you are not very smart if you believe US policy would entail shooting at Israeli planes in this day and age. The number of reasons as to why this is a moronic view are too numerous to list. There's not enough space on the Internet.