Flight number record
DL 1748
Delta Air Lines · Boston to Detroit
- Route
- BOS → DTW
- Departs
- 09:00
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1748, check with Delta Air Lines.
DL 1748 earns an A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.3%. When something does go wrong the average delay runs close to two hours. That rests on 365 flights, with a median arrival 9 minutes early.
Set against the rest of the country, DL 1748's record is 10 points better than the US average of 77.3%. That gap is worth roughly 96 fewer late arrivals for every thousand flights.
Key figures
On time
86.9%
Arrivals under 15 minutes late, of 359 completed flights
Avg delay
105 min
Across delayed arrivals only, not all flights
Cancelled
1.64%
National rate is 1.89%
1 hour+ late
5.0%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. The median arrival is 9 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Schedule
When DL 1748 flies
DL 1748 flies BOS to DTW without a single fixed slot. Its most common scheduled departure was 09:00, used on 188 of 365 flights, with 09:05 (67 flights) and 09:15 (53 flights) next.
- Departs 09:00188 flights51.5%
- Departs 09:0567 flights18.4%
- Departs 09:1553 flights14.5%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 09:00 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and DL 1748 runs 3 points better at 86.9%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 1748 next to BOS to DTW
Every carrier on BOS to DTW combined arrived on time 75.7% of the time across 2,575 flights, so DL 1748 is 11 points ahead of it. Delta flew 1,718 flights on the same city pair under all its flight numbers, including this one, and those ran 78.1% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 6 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1748 | 365 | 86.9% | 105 min | 1.64% | A |
| All Delta Air Lines on BOS–DTW | 1,718 | 78.1% | 79 min | 2.21% | B |
| All carriers on BOS–DTW | 2,575 | 75.7% | 78 min | 2.80% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1748 quarter by quarter
DL 1748 did not run the same all year. Its best quarter was Apr–Jun 2026 at 95.6% on time and its weakest Jan–Mar 2026 at 80.5%, a swing of 15 points on roughly 73 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights93.3%
- Oct–Dec 202592 flights85.7%
- Jan–Mar 202690 flights80.5%
- Apr–Jun 202691 flights95.6%
- Jul–Sep 202662 flights82.0%
Scale runs 70% to 100%.
By weekday, DL 1748 ranged from 80.8% on Sunday to 92.0% on Monday. With about 52 flights behind each day, a spread of 11 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late DL 1748 runs when it is late
DL 1748 often beats the schedule: 138 of 359 completed flights, 38%, arrived 15 minutes or more early. The 47 late arrivals split 16 under half an hour, 13 between 30 and 60 minutes, and 18 an hour or more.
- 15+ min early138 flights38.4%
- Within 15 min174 flights48.5%
- 15–29 min late16 flights4.5%
- 30–59 min late13 flights3.6%
- 1–2 hours late5 flights1.4%
- 2+ hours late13 flights3.6%
Scale runs 0% to 100%.
Share of 359 completed flights by arrival against schedule.
10 of 38 late departures made up the time and arrived on time, 26% of them. In the other direction, 19 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at DTW.
The worst days
Worst days for DL 1748
The latest arrival of the period was on 28 December 2025, 8 hours 19 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. Three of the five worst days fell in January 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 28 December 2025 | 8 hours 19 minutes | Late-arriving aircraft |
| 28 January 2026 | 8 hours 17 minutes | Carrier |
| 27 December 2025 | 7 hours 24 minutes | Carrier |
| 25 January 2026 | 6 hours 50 minutes | Extreme weather |
| 1 January 2026 | 5 hours 16 minutes | Carrier |
Delay causes
Why DL 1748 runs late
Carrier accounts for 57% of the 4,940 delay minutes carriers reported here, and the remaining four split what is left.
- 57%Carrier
- 23%National Airspace System
- 12%Late-arriving aircraft
- 9%Extreme weather
The largest share of delay minutes, 57%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,801 of the 4,940 delay minutes reported here. The split is drawn from 4,940 delay minutes reported on DL 1748.
Cancellations sit at 1.64% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
5.0% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last close to two hours, which a normal layover absorbs.
The 632 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
Every one of the 365 flights under DL 1748 in the data flew BOS to DTW. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 365 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking DL 1748
For a booking, read DL 1748 as 86.9% on time with 1.64% cancelled over 365 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- BOS to DTW, every carrier and departure
- DTW to BOS, the return direction
- Delta Air Lines 1019 on the same route94.1%
- Delta Air Lines 2222 on the same route80.7%
- Delta Air Lines 1432 on the same route68.6%
- Boston Logan International (BOS) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.