Originally Posted by
joe_miami
We're talking about the very specific example of flying to a U.S. territory in the far east of the Caribbean. Obviously, this scenario doesn't apply to probably 98% of the average traveler's flights, just like flight cancellations don't apply to 98% of a traveler's flights. But as with flight cancellations, a very small amount of foresight can save a lot of time and hassle. If I unexpectedly found myself with 4 or 8 hours in Punta Cana or Puerto Plata, I'd rather go for a nice seaside lunch or dinner than sit at PUJ or POP.
Totally get your frustration because many were being unnecessarily harsh to your point. Never really thought about taking a passport on domestic flights that cross international airspace. That’s a good idea to start doing. Your point is well taken.
As to the reason for the notice to the OP from UA... there is a 0% chance UA has ever or will ever require or even suggest taking a passport on such flights for that reason. The notice the OP saw was either generic language with all flights or a bug.