There are always air marshals on US carriers flying to Tel Aviv, including Delta. And they're usually blatantly obvious. On my last flight, one of them made no effort to hide.

It is true that El Al's security is more extensive than the US carriers, but it's hard to say if this is more of the illusion of El Al or genuinely protective. I can say that El Al denies Richard Reid the opportunity to fly, but American let him on board.

In any case, the US carriers often require their crews to be "Tel Aviv certified," so they have had special training. There are always special security measures in place, even if they seem kind of stupid.

On the way back, all flights from Ben Gurion Airport have the same security procedures, so it doesn't matter if you fly on El Al or Delta.

Although I understand your concern, I do not think there is any reason to switch airlines. Again, have a great trip here, and let us know if you have other questions.