From United's timetable, November 1*:

IAD-LGA

UA758 IAD 7:00 AM LGA 8:16 AM 733 1h16m
UA846 IAD 8:55 AM LGA 10:11AM 752 1h16m
UA7424~ IAD 10:30AM LGA 11:46AM CRJ 1h16m
UA7323~ IAD 12:33PM LGA 1:49 PM CRJ 1h16m
UA360 IAD 2:37 PM LGA 4:03 PM 733 1h26m
UA7367~ IAD 5:25 PM LGA 6:51 PM CRJ 1h26m
UA7309~ IAD 7:20 PM LGA 8:46 PM CR7 1h26m
UA7369~ IAD 9:35 PM LGA 10:49PM CRJ 1h14m

IAD-EWR

UA7138~ IAD 8:28 AM EWR 9:38 AM ER4 1h10m
UA7295~ IAD 11:02AM EWR 12:12PM CRJ 1h10m
UA8005~ IAD 12:33PM EWR 1:54 PM ER4 1h21m
UA7192~ IAD 2:40 PM EWR 4:01 PM CRJ 1h21m
UA8036~ IAD 4:45 PM EWR 6:29 PM ER4 1h44m
UA7972~ IAD 8:40 PM EWR 9:59 PM ER4 1h19m
UA8027~ IAD 9:40 PM EWR 10:59PM ER4 1h19m

IAD-JFK

UA7302~ IAD 8:15 AM JFK 9:29 AM CRJ 1h14m
UA7346~ IAD 10:30AM JFK 11:44AM CR7 1h14m
UA7310~ IAD 12:33PM JFK 1:47 PM CRJ 1h14m
UA7381~ IAD 2:50 PM JFK 4:04 PM CR7 1h14m
UA7318~ IAD 4:55 PM JFK 6:09 PM CRJ 1h14m
UA7418~ IAD 7:20 PM JFK 8:34 PM CR7 1h14m
UA7320~ IAD 9:50 PM JFK 11:04PM CRJ 1h14m

* November 1: First post-termination day of international service from JFK.

Another note: The IAD-JFK CR7 does not linger in the schedule for long, and I believe it is not a exPlus-equipped aircraft per the seatmap.