Flight number record

DL 1748

Delta Air Lines · Boston to Detroit

Route: BOS → DTW
Departs: 09:00
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1748, check with Delta Air Lines.

DL 1748 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 12 points better than the national rate of 77.6%. When something does go wrong the average delay runs close to two hours. That rests on 365 flights, with a median arrival 12 minutes early.

Set against the rest of the country, DL 1748's record is 12 points better than the US average of 77.6%. That gap is worth roughly 121 fewer late arrivals for every thousand flights.

On time

89.7%

Arrivals under 15 minutes late, of 358 completed flights

Avg delay

115 min

Across delayed arrivals only, not all flights

Cancelled

1.92%

National rate is 1.81%

1 hour+ late

4.5%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 12 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.

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 244 of 365 flights, with 09:05 (73 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 09:00244 flights66.8%
Departs 09:0573 flights20.0%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

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 84.1%, and DL 1748 runs 6 points better at 89.7%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

DL 1748 next to BOS to DTW

Every carrier on BOS to DTW combined arrived on time 77.6% of the time across 2,591 flights, so DL 1748 is 12 points ahead of it. Delta flew 1,712 flights on the same city pair under all its flight numbers, including this one, and those ran 79.6% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 8 points.

DL 1748 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1748	365	89.7%	115 min	1.92%	A
All Delta Air Lines on BOS–DTW	1,712	79.6%	77 min	2.04%	B
All carriers on BOS–DTW	2,591	77.6%	75 min	2.12%	B
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1748 quarter by quarter

DL 1748 did not run the same all year. Its best quarter was Jul–Sep 2025 at 96.7% on time and its weakest Jan–Mar 2026 at 80.5%, a swing of 16 points on roughly 91 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 202592 flights96.7%
Oct–Dec 202592 flights85.7%
Jan–Mar 202690 flights80.5%
Apr–Jun 202691 flights95.6%

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1748 ranged from 84.6% on Sunday to 95.9% 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.

Delay causes

Why DL 1748 runs late

One category carries most of the weight here. Carrier accounts for 57% of the 4,264 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Carrier
57%
National Airspace System
19%
Late-arriving aircraft
14%
Extreme weather
10%

The largest share of delay minutes, 57%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 2,435 of the 4,264 delay minutes reported here. The split is drawn from 4,264 delay minutes reported on DL 1748.

Cancellations sit at 1.92% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 4.5% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

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 89.7% on time with 1.92% cancelled over 365 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures