UA 2661 then UA 1593 at San Francisco
Philadelphia → San Francisco → Houston
Timetable, San Francisco time
09:22UA 2661 from Philadelphia at the gatealso NH 7021, CA 7299, VA 8451, NZ 9365
23:15UA 1593 to Houston leaves the gatealso EK 6028, NZ 9192
13 h 53 apart on the timetable
UA 1593 leaves 13 h 53 after UA 2661 arrives on the timetable: more than half a day, so not a connection we count.