Air France KLM’s Flying Blue program should be interesting to U.S. frequent flyers for several reasons: they offer one-way awards; they are an American Express Membership Rewards, Citi Thank You points, and a Chase Ultimate Rewards transfer partner; they have far more award space on their own flights than Delta has access to; they have most of their partners available for online booking.
And they have a bunch of business class award routes on sale to anywhere in Europe (including Israel for the same price).