With 50,000 spg points your best bet is skyteam via Alitalia, they are only 50,000 points per ticket, and you can try for a Delta nonstop. However, they no longer allow returning points to the FF program if you decide to cancel. AA is 90,000 points and CO is 75,000 points. You cannot transfer SPG points into CO points at a worthwhile rate, but you can put them into a partner airline to redeem on CO. The Lan route is no longer worth it as they have a new way of charging km and it comes out to be a lot of miles to TLV.