AA 1997 then UA 5238 at O'Hare
St Louis → Chicago → Green Bay
Timetable, Chicago time
09:00AA 1997 from St Louis at the gate
13:30UA 5238 to Green Bay leaves the gate
4 h 30 apart on the timetable
The last days
AA 1997 and UA 5238 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.