DL 873 then UA 1517 at DFW
New York LaGuardia → Dallas-Fort Worth → Chicago O'Hare
Timetable, Dallas-Fort Worth time
20:23DL 873 from New York LaGuardia at the gate
17:44UA 1517 to Chicago O'Hare leaves the gate
21 h 21 apart on the timetable, overnight
UA 1517 leaves 21 h 21 after DL 873 arrives on the timetable: more than half a day, so not a connection we count.