The USA found the USSR had been arming the Arab nations for a year leading up to this war. The USSR provided people to trained the Egyptian infantry, to remain in place when Israeli tanks approached and use their RPGs when they could hit the Israeli tanks on the side. (Something they had not done in previous conflicts!) The USSR had satellites in orbits to cover the conflict, the USA did not. So the USA flew the SR-71 daily to get the intelligence needed.
The USA was very concerned when they recieved indications Israel was getting ready to use nuclear weapons. That would change the political dynamics in the Middle East making them far worst. Whether it was real or a bluff, it got the desired response from Washington. On Oct. 9th, El Al Airlines started up to twenty flights from the USA to Israel per day. On Oct. 10th the USSR started its airlift to Syria. On Oct.14th, the USA started its airlift in full force... C-5s and C-141s. The USA provided fighter protection for the airlift to Israel from Spain and the carrier USS Independence in the Mediteranean about six hundred miles from Israel. US surface ships were stationed every three hundred miles to provide radar surveilence. The USS Guadacanal (amphib carrier) stood by in case any American civilians needed to be evacuated from any war zone. At 150-miles from Israel, the IAF provided fighter protection the rest of the way to Israel. The US airlift provided more tonnage to Israel than the USSR had to Syria and Egypt, even though the USSR started days earlier, plus the USSR was far closer to its allies than the USA was to Israel. The USA airlifted 22,325 tons of materiel to Israel, by October 30th. During the same general time, the Soviets airlifted 12,500–15,000 tons of supplies. This really troubled the USSR.
Look up, "Operation Nickel Grass" America's re-supply efforts. URL;
http://en.wikipedia.org/wiki/Operation_Nickel_Grass
As it turned out the USA going to DEFCON 2 was a wise decision! The USSR had wanted to send transports with paratroopers to help its Syrian and Egyptian allies. Whereas the IAF had control of the air over Syria, what would have been the repercussions "IF" IAF fighters shot down transport
s full of Soviet paratroopers????