AA 1494 then UA 5940 at O'Hare
San Diego → Chicago → Tucson
Timetable, Chicago time
04:49AA 1494 from San Diego at the gate
19:54UA 5940 to Tucson leaves the gate
15 h 05 apart on the timetable
UA 5940 leaves 15 h 05 after AA 1494 arrives on the timetable: more than half a day, so not a connection we count.