AA 2258 then UA 5191 at O'Hare
Las Vegas → Chicago → Lancaster
Timetable, Chicago time
12:52AA 2258 from Las Vegas at the gate
08:50UA 5191 to Lancaster leaves the gate
19 h 58 apart on the timetable, overnight
UA 5191 leaves 19 h 58 after AA 2258 arrives on the timetable: more than half a day, so not a connection we count.