I guess that would be different if I was flying first or business class.
This is specifically to not to take up any extra room than is necessary. The only room it takes up is essentially the width of the HMD itself (even negating the strap)!
There's always the fear of losing stuff when you're moving objects around so much, too. One less thing to worry about.
So I don't fly with a tablet any more haha! Although, I get that time has passed and I would no longer be accosted so much, I assume. Must be pretty common now. My story takes place in ~2011 with the Motorola Xoom tablet. I guess they had never seen a tablet before.
I was also working hard on a plane one time, writing code to access barometer data on mobile devices to build a distributed weather sensor network that could be activated in software. The flight attendant came by and told me, "okay, time to put your toys away sweetie" referring to my tablet and phone. Oooooooooh my god.
Small: https://www.amazon.com/gp/product/B0C4YFV9F9/
Medium: https://www.amazon.com/dp/B09QPN321B
Syntech recommend medium. Folks likely would prefer small, but caution about cracking glass front.
That said, security rules vary from airport to airport. SFO with TSA Pre is practically a no-op, but CDG security requires that you remove from carry-on any device with a >20cm dimension!
The 3S has an IR blaster that allows it to work in total darkness. Meta also enabled a travel mode[1] a couple of OS revisions ago (back in June or so).
[1] https://www.meta.com/help/quest/articles/in-vr-experiences/o...
Pre-iPad, most airport staff (who aren't hardcore techies, or might not have the privilege of higher education) might think of a tablet as a laptop anyway.
That said, the last time I had the opportunity to use my VP on a plane I just used my kindle and laptop instead.