Just thought I'd post our experiences with El Al and an infant in economy. They don't provide seat-belt extenders - you just hold the child on your lap. This was absolutely fine with us, as it made for a happier child, but I did wonder what would happen in severe turbulence. They moved us to the bulkhead on the outbound, which was very pleasant, offered us water/blanket/bassinet at the start of the flight, and generally looked after us. Not so much on the return, but that flight was packed. We declined the bassinet because we didn't see that our daughter would stay in it, and the extra space was useful.

Unfortunately we didn't get a bulkhead on the return. The lady in front complained that our daughter was pushing her seat, to which I replied that she had fully reclined her seat after takeoff, and this did make it rather difficult to keep her away, but that we would do our best (actually, I think she may have mistaken the feeling of us getting stuff in and out of the seat pocket). I lost sympathy when I observed said lady resting her knees/feet against the seat in front of her and visibly pushing it!

We asked if we could eat at separate times on the return so one of us could hold the baby while the other ate. No problem.

El Al to/from Luton is great, at least at the times we flew. Short or no security queues, and no traffic. We had lounge access via Priority Pass at both ends, but we didn't really have time to get there, so I didn't check them out (and I think Luton doesn't let kids in...)

Daughter was a dream on the flight. One squeak on the first landing, and that was it. I think she's trying to persuade us to risk taking her business class...