We all know that Israel and most of the Arab countries nearby are not even remotely friendly. Suppose that an Israeli commercial plane (El Al, for example) had engine trouble and had to make an emergency landing in Saudi Arabia or Bahrain or Dubai or possibly Iran? What would that country - who doesn't acknowledge that Israel exists - do with 300 passengers and the plane?

Most of the Arab states would allow an emergency landing. Iran would be a no. But an Israeli airliner has no business being in their airspace to begin with.

Here is an old but interesting example. 30 – 35 years ago, before the days of GPS most aircraft were fitted with Emergency Position Indicating Radio Beacon (EPIRB)s that could be used to locate a crashed plane. The devices would automatically activate in a crash. Satellites passing overhead would ID the location.
One day, decades ago the local Lake Ontario Coast guard office got a strange call from a Soviet “citizen” stating a crash had just occurred. The “citizen” gave a description of the location – a spot at the Rochester airport. Police were dispatched and quickly discovered a couple of kids rifling through private planes. They must have found the EPIRB and tossed it out the window when it didn’t work like a CB. That activated it . The Soviets knew, based upon our satellite location at that instant, that it would take our equipment another 10 -15 minutes to detect the crash so someone took it upon himself to call and report it.
Nice! That became a model of cooperation.

Maybe just maybe people would treat each other with respect.

Well Israel and Saudi Arabia don’t have formal diplomatic relations, but they’re both allied with the United States and they conduct under the table diplomacy with each other. The UAE (of which Dubai is a part) are anti-Israeli, but they aren’t really big enough to risk drawing the ire of Israel or the US. Bahrain don’t really have any kind of relations with Israel, but aren’t really actively hostile towards Israel ether. As for Iran, I’d question what an Israeli airliner was doing over Iranian airspace in the first place.

Every one of those countries would allow the plane to land at the nearest airport, rather than run the risk of the thing falling from the sky on top of THEIR OWN citizens and real estate. Even ignoring this clear and obvious motivation for acting right, there is that other eternal self interest motive. You allow them and even assist them in landing to assure that when it’s your plane’s turn to malfunction, YOU have a place to land.

In fact I’m fairly certain that every country involved in cross border air travel is obligated by treaties to assist and prioritize assistance to ANY civilian plane in trouble regardless of its state of origin.

I really don’t think Dubai would be a problem. I have family who live there and they are very tolerant of different religions and cultures.