What is the best way to building flight hours?

I suspect that the cost of flying in the US will be much less than flying in Israel so from a cost perspective you should build flight hours in the US. As far as getting a job with a US airline, or even working as a flight instructor, that won't be possible unless you get a visa that allows you to work in the US. There is no shortage of pilots or instructors in the US; getting a work visa might be impossible. In addition you will need to file a request for training and will need to p several background checks to be allowed to get commercial or instrument ratings in the US since 9/11.