Carrier route record
DLDTW→BUF
Delta Air Lines · Detroit to Buffalo
- Flights
- 443
- Period
- July 2025 to June 2026
- Share of route
- 41%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on DTW to BUF lands a B, level with the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by close to two hours on average. That is a workable record, not a spotless one. That rests on 443 flights, with a median arrival 8 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Delta on DTW to BUF from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.1%
Arrivals under 15 minutes late, of 434 completed flights
Avg delay
116 min
Across delayed arrivals only, not all flights
Cancelled
1.81%
National rate is 1.81%
Whole route
78.9%
Every carrier on DTW to BUF, 1,091 flights
These figures cover 443 flights between July 2025 and June 2026. Beyond the headline rate, 9.9% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Delta against every carrier on DTW to BUF
Delta flew 443 of the 1,091 flights on DTW to BUF, about 41% of it. Its 78.1% on time is about level with the route as a whole at 78.9%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from Republic at 100.0% to Delta at 78.1%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 7 | 100.0% | — | 14.29% | A− |
| SkyWest Airlines | 641 | 79.2% | 99 min | 1.56% | B |
| Delta Air Lines (this page) | 443 | 78.1% | 116 min | 1.81% | B |
Departure window
When Delta runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 443 flights.
- 5am–8am—
- 8am–11am22 flights—
- 11am–2pm—
- 2pm–5pm60 flights84.2%
- 5pm–8pm—
- 8pm–5am361 flights77.0%
Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 2pm–5pm slot at 84.2% on time, ahead of 8pm–5am at 77.0%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 8pm–5am window is the busiest, with 361 flights scheduled in it.
Across the year
Delta on DTW to BUF through the year
July is the worst month at 51.6% on time, 45 points below September, the best at 96.7%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. January was the busiest month here, with 56 flights.
Across the week, Thursday is the strongest day at 87.3% on time and Monday the weakest at 69.8%. 18 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Delta runs late on this route
One category carries most of the weight here. Carrier accounts for 66% of the 11,000 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.
- 66%Carrier
- 16%Late-arriving aircraft
- 10%National Airspace System
- 7%Extreme weather
The largest share of delay minutes, 66%, 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 7,299 of the 11,000 delay minutes reported here. The split is drawn from 10,988 reported delay minutes.
Cancellations sit at 1.81% against a national 1.81%, which is ordinary. Diversions add another 0.23%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.9% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 241 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 2pm–5pm window matters as much as it does.
The return leg is a different operation and performs like one: it runs 84.1% on time across 443 flights, 6 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 6 points of difference.
One caution: this is a thin sample. 443 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 Delta on DTW to BUF
Put together: treat all of this as provisional. 443 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 78.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 434 completed flights over 12 months sit behind that.
Related
Where to go next
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.