Schedule: the flights that flew on Tuesday, Nov 3, re-dated. Real flights replace these once airlines file their FAA flight plans, usually about a day ahead.

DELTA · FLIGHT DL 1661 SCHEDULED · TYPICAL SCHEDULE
Tomorrow

DL 1661 · BOS → DCA

departs 2:30 PM ET · arrives 4:16 PM ET
Forecast issued Mon 9:00 PM ET · 18h before departure

DL 1661 isn’t flying BOS → DCA on Tue, Nov 10

This listing came from a typical schedule. According to the FAA, DL 1661 flies these legs that day: