Originally Posted by
Tries
I got it! Here is it:
"If you are arriving into Terminals 1, 2 or 3 you can remain on the secure side of the checkpoint and walk between terminals without exiting security. If you arriving into Terminal 5 and departing from Terminals 1, 2 or 3 then you will have to go through the screening process to get to your gate area.
If you have any additional questions, please let me know.
Regards,
Amanda Smith
Aviation Department"
That doesn't really answer your questions, however, especially the parts about whether you can stay airside overnight, and whether the screening stations operate 24/7.
Given that I am an anonymous poster on an IBB, take this with a grain of salt...but I'd say the following:
24/7 screening? Unlikely, since ORD has practically zero domestic outbound flights between 11 pm and 5 am. The checkpoints re-open around 4 a.m., IME. There may be a single 24/7 checkpoint for staff but I wouldn't count on being able to use it.
Staying airside overnight? Definitely doable. In fact there are probably dozens of stranded pax who do this every night, since ORD is the kind of place where pax miss connecting flights on a routine basis. It would probably help if you had the boarding pass for your onward flight, but I'm guessing you can just find a quiet spot and not be bothered. ORD is a huge place and I don't think the cleaning crew really gives a rip about a smattering of passengers scattered around the place.