Carrier performance at one airport
DL→DEN
Delta Air Lines at Denver International
- Departures
- 11,497
- Period
- September 2025 to August 2026
- Routes
- 9
- Rank here
- #1 of 9
Delta Air Lines at Denver lands a B, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 11,497 flights, of which Delta Air Lines flew 11,497 at 83.1% on time.
Measured against the airport rather than the country, Delta Air Lines runs 6 points ahead of the 76.7% weighted average across all carriers at DEN. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
83.1%
11,299 completed departures
Avg delay
75 min
Across delayed flights only
Cancelled
1.37%
At DEN, this carrier only
Rank here
#1
Of 9 carriers clearing the floor at DEN
These figures cover 11,000 flights between September 2025 and August 2026. The median arrival is 10 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.
Against the competition
Every carrier at DEN, ranked
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 83.1% of the time; JetBlue Airways manages 65.7%. Sample sizes sit next to every figure, because a two-point gap across 1,258 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines (this page) | 11,497 | 83.1% | 75 min | 1.37% | B |
| SkyWest Airlines | 75,223 | 80.4% | 78 min | 1.09% | B |
| United Airlines | 107,895 | 78.9% | 65 min | 0.41% | B+ |
| Frontier Airlines | 22,870 | 78.5% | 68 min | 0.77% | B+ |
| Alaska Airlines | 2,879 | 78.1% | 57 min | 0.66% | B+ |
| American Airlines | 8,936 | 77.1% | 105 min | 1.97% | B |
| Allegiant Air | 373 | 76.5% | 94 min | 0.54% | B+ |
| Southwest Airlines | 88,424 | 69.5% | 54 min | 0.72% | C+ |
| JetBlue Airways | 1,258 | 65.7% | 93 min | 4.61% | C− |
JetBlue Airways cancels 4.6% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Where Delta Air Lines flies from DEN
Delta Air Lines operates 9 routes out of DEN with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DEN to ATL · Atlanta | 2,807 | 85.8% | 61 min | 1.18% | A |
| DEN to MSP · Minneapolis | 1,796 | 82.2% | 68 min | 1.06% | B |
| DEN to SLC · Salt Lake City | 1,698 | 82.0% | 78 min | 0.35% | B+ |
| DEN to DTW · Detroit | 1,247 | 86.8% | 79 min | 0.32% | A+ |
| DEN to LGA · New York | 1,033 | 79.7% | 83 min | 4.84% | B− |
| DEN to JFK · New York | 937 | 87.7% | 77 min | 2.45% | A |
| DEN to SEA · Seattle | 868 | 78.5% | 86 min | 0.92% | B+ |
| DEN to LAX · Los Angeles | 746 | 81.2% | 101 min | 1.34% | B |
| DEN to BOS · Boston | 365 | 71.7% | 61 min | 1.10% | C |
Flight by flight
Delta Air Lines flight numbers from DEN
16 Delta Air Lines flight numbers leaving DEN flew their main route often enough to have a record of their own. Grouped by destination.
- DL 341to ATL 06:0093.9%
- DL 346to ATL 10:5079.2%
- DL 431to ATL 07:0593.9%
- DL 840to ATL 16:4380.7%
- DL 995to ATL 12:0086.0%
- DL 2235to ATL 09:3986.0%
- DL 1745to DTW 06:0590.9%
- DL 2787to DTW 10:2584.3%
- DL 336to JFK 06:4091.0%
- DL 2002to LAX 07:2589.5%
- DL 398to LGA 07:1087.1%
- DL 1129to MSP 06:0091.7%
- DL 1731to SEA 06:3089.4%
- DL 1581to SLC 07:0591.1%
- DL 2544to SLC 05:3088.2%
- DL 2663to SLC 18:2369.1%
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against 17 points between the best and worst carrier.
- 5am–8am3,344 flights91.0%
- 8am–11am1,083 flights85.7%
- 11am–2pm2,977 flights79.6%
- 2pm–5pm2,022 flights81.9%
- 5pm–8pm1,405 flights68.8%
- 8pm–5am666 flights88.6%
Scale runs 60% to 95%.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.0% of the time, against 68.8% for the evening window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 3,344 flights scheduled in it.
Across the year
Seasonal pattern
December is the weak month at 73.4% on time, against 89.8% in April. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. July was the busiest month here, with 1,082 flights.
Delay causes
What holds this operation up
- 41%Late-arriving aircraft
- 40%Carrier
- 16%National Airspace System
- 3%Extreme weather
- 0%Security
41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 143,000 reported delay minutes here, that single category outweighs weather by 12 to one. The split is drawn from 142,820 reported delay minutes.
Cancellations sit at 1.37% against a national 1.89%, which is ordinary. Diversions add another 0.36%.
6.0% 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 a little over an hour, which a normal layover absorbs.
The sample behind these figures is 11,497 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 89.8% on time and December 73.4%, a swing of 16 points. If the dates move at all, move them out of December before you think about anything else. 11,299 completed flights over 12 months sit behind that.
Common questions
Delta Air Lines at DEN
How often is Delta Air Lines at DEN delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 16.9% of the 11,497 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on Delta Air Lines at DEN?
Delta Air Lines leads at 83.1% on time across 11,497 flights. JetBlue Airways is at the other end on 65.7%, a gap of 17 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on Delta Air Lines at DEN?
The 5am–8am departure window is the strongest at 91.0% on time. The 5pm–8pm window is the weakest at 68.8%, 22 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are December delays on Delta Air Lines at DEN?
December is the weakest month at 73.4% on time, compared with 89.8% in April. Across the year that is 16 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- Delta Air Lines network-wide record
- Denver International (DEN) all carriers
- DEN to ATL route record85.8%
- DEN to MSP route record82.2%
- DEN to SLC route record82.0%
- DEN to DTW route record86.8%
- Denver, Salt Lake City, Phoenix and Las Vegas: the Mountain West hubs
- Why the first flight of the morning is statistically safest
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.