Originally Posted by
Kmxu
AA forum is a better place to ask about the airside shuttle from AA concourses to LX departure (Terminal M).
Edit: UA App gives a direction from PL to gate M7. The total time is 65 min, with 30 min budgeted for security check.
Sixty five minutes seems way too pessimistic but maybe they're assuming absolutely everything goes wrong.
I'd keep an eye on the Midwest forum as an O'Hare employee who posts at times often will mention any significant changes coming up to inter-terminal transportation. He's the one gave the heads-up on when the ATS was going back into service well in advance. BTW, the airside bus, pre-COVID, stopped at both T1 and T3 before going to T5.