The audio isn't noise cancelling. The speakers are on the strap right by your ears so you'll still hear everything else around you. If anything my concern on flights would be that someone next to me can hear my audio, not that I can't hear them. (but maybe you can also use AirPods)
You can also adjust your "immersion level". As in, have the screen floating in front of you and still see the space around you, or have reality totally blanked out. Seems like at a low immersion level you'd have no problem turning to address someone trying to get your attention. The worst part might be how ridiculous you look talking to and addressing someone normally while wearing these. (though perhaps like the AirPods, the perception of it being a goofy look will fade with time)
Ah that totally makes sense and seems like it's Apple's way of tacitly acknowledging that people around you can hear the built-in speakers. With the immersion level turned down it seems like the noise cancelling AirPods will be a bigger hurdle to someone getting your attention than the headset itself. (putting aside the silliness you'll feel talking to someone while casually wearing it)
They also announced new feature to airpods something liked auto adaptive immersion that they detect what to noise cancel and what not dynamically depending on changing environment. On video they showed someone when someone start talking to you they will reduce immersion and the same when you start talking.
Similarly when when showed up close to you while you are in fill apple vision pro VR impression mode they will reduce it see this person slightly blended with your VR world
You can also adjust your "immersion level". As in, have the screen floating in front of you and still see the space around you, or have reality totally blanked out. Seems like at a low immersion level you'd have no problem turning to address someone trying to get your attention. The worst part might be how ridiculous you look talking to and addressing someone normally while wearing these. (though perhaps like the AirPods, the perception of it being a goofy look will fade with time)