UA 1590 then AA 6238 at DFW
Newark → Dallas-Fort Worth → Amarillo
Timetable, Dallas-Fort Worth time
18:32UA 1590 from Newark at the gate
08:25AA 6238 to Amarillo leaves the gate
13 h 53 apart on the timetable, overnight
AA 6238 leaves 13 h 53 after UA 1590 arrives on the timetable: more than half a day, so not a connection we count.