About 1 in 3 DL 5721 flights from Boston arrived 15+ minutes late, diverted or cancelled over the past year (39%); 9.9% were cancelled. The typical flight landed 6 minutes early.
DL 5721: BOS → LGA
Scheduled to leave Boston at 5:00 p.m. local time, operated by Republic Airways as YX 5721. Over the past year it arrived on time 61% of the time (314 flights), in line with other DL flights on the route at that hour (62%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 48 | 63% |
| Tuesday | 47 | 60% |
| Wednesday | 47 | 60% |
| Thursday | 45 | 51% |
| Friday | 45 | 64% |
| Saturday | 35 | 83% |
| Sunday | 47 | 49% |
Why it was late
All flights BOS → LGA · Connecting off DL 5721? Check the risk
Questions
How often is DL 5721 from BOS to LGA late?
Delta Air Lines 5721 from Boston, MA to New York, NY arrived 15 or more minutes late, was diverted or was cancelled on 39% of 314 scheduled flights between September 2025 and August 2026. 9.9% were cancelled.
Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check Delta Air Lines for today's flight. Method.