UA 5209 then AA 1387 at O'Hare
Washington → Chicago → Denver
Timetable, Chicago time
07:30UA 5209 from Washington at the gate
21:05AA 1387 to Denver leaves the gate
13 h 35 apart on the timetable
AA 1387 leaves 13 h 35 after UA 5209 arrives on the timetable: more than half a day, so not a connection we count.