To avoid lengthy questioning, skip El Al and take Air Sinai between CAI and TLV. Air Sinai is only coach and doesn't have much pitch, but it's a very short flight.

My experience is 2 hours of the same questions over and over again on El Al and zero questions on Air Sinai.

If you go the Europe route, you can use miles on UA to LHR and then take Olympic to CAI with a stop in Athens. I've done the Olympic flight from Athens to Cairo and it was very good and relatively cheap.