Why does Israel only buy American?

Why not buy fighters from other countries.

For example, Typhoons, Rafales, Su or Migs for the air force?

And risk losing all the aid and other support that the US gives?

They'd have to have rocks in their head.

couldn't it be in addition to the us aid?

are israel's F-15Is s good as any other fighter out there (other than the F-22 of course)

Israel was not a major client of US made arms untill after 1967. Almost every weapon in the IDF was either French, British or Belgian. After 1967 the European nations either embargoed israel or refused to sell top of the line equipment. Israel had no choice but to turn t the USA. USA hardware, espcially aircraft, is usually as good if not better than other system in the market, and Israel recieves a 2-3 billion US $ aid budget which allows us to buy these products with out increasing our already insanel military spending. However its not copletely accurate that we do not us any other equipment. For starters we use alot of Israeli made or developed hardware. We also have European made wheeled vehicles(heavy trucks and 4X4 vehicles) like Land Rovers and Czech made Tatra trucks. We also have German made submarines and missile boats. Specific unit also have acsess to non american fire arms, like the SPAS-15, MP-5, Glock pistols, and other weapons....

Could it be easier to bastardise american machinery and hardwear?

If you could get military grants (no repayment) and "sub-prime" loans... who wouldn't go for this deal. Once the IDF received a sub-prime loan and they didn't need the money at the time. They invested the money and eight years later doubled their money! They repaid the USA and the interest equalled the original amount of the loan!!
Israel makes very good sub-system and smaller weapon systems such as the Gabriel anti-ship missile, Barack Missile (seaborne SAM), Python-5 missile, ECM/ESM gear, etc. To the Israeli Government a major weapon design system is something as large as the Merkerva MTB. Something like a first class

They (Israel) do participate in technology sharing arrangements with other countries, the most recent I know of is Derby and Darter A2A Missiles designed with South Africa. The IDF/AF worked with USAF back in the late 1970's on a HMDS! The USAF dropped out of the program but the US Army picked up the USAF's part in the program. That is why the AH-64 Apache was the first major weapon to use a HMDS back in 1983!