Carrier route record
DLSEA→DFW
Delta Air Lines · Seattle to Dallas-Fort Worth
- Flights
- 712
- Period
- July 2025 to June 2026
- Share of route
- 14%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on SEA to DFW sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 712 flights. The strongest carrier on the route with a full sample, Alaska Airlines, flew 1,755 at 78.9% on time.
The US average over the same twelve months is 77.6%, so there is little to separate Delta on SEA to DFW from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
75.1%
Arrivals under 15 minutes late, of 696 completed flights
Avg delay
83 min
Across delayed arrivals only, not all flights
Cancelled
1.69%
National rate is 1.81%
Whole route
77.6%
Every carrier on SEA to DFW, 5,233 flights
These figures cover 712 flights between July 2025 and June 2026. Beyond the headline rate, 8.9% 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 SEA to DFW
Delta flew 712 of the 5,233 flights on SEA to DFW, about 14% of it. Its 75.1% on time is 3 points worse than the route as a whole, which runs 77.6%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from Alaska at 78.9% to Frontier at 46.4%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: about a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 1,755 | 78.9% | 44 min | 1.03% | B |
| American Airlines | 2,738 | 77.6% | 98 min | 2.81% | B |
| Delta Air Lines (this page) | 712 | 75.1% | 83 min | 1.69% | B |
| Frontier Airlinesthin sample | 28 | 46.4% | 84 min | 0.00% | F+ |
No carrier stands out. Alaska tops the table at 78.9%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Delta flight numbers on SEA to DFW
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 712 flights.
- 5am–8am—
- 8am–11am361 flights79.2%
- 11am–2pm—
- 2pm–5pm1 flights—
- 5pm–8pm350 flights70.9%
- 8pm–5am—
Scale runs 60% to 85%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 79.2% of the time, against 70.9% for the evening window. That is 8 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 361 flights scheduled in it.
Across the year
Delta on SEA to DFW through the year
December is the weak month at 60.3% on time, against 86.4% in March. 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. March was the busiest month here, with 62 flights.
Across the week, Tuesday is the strongest day at 80.4% on time and Sunday the weakest at 67.3%. 13 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 61% of the 14,000 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.
- 61%Carrier
- 27%Late-arriving aircraft
- 11%National Airspace System
- 1%Extreme weather
The largest share of delay minutes, 61%, 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 8,792 of the 14,000 delay minutes reported here. The split is drawn from 14,356 reported delay minutes.
Cancellations sit at 1.69% against a national 1.81%, which is ordinary. Diversions add another 0.56%.
Connections and stage length
What a delay here costs
8.9% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, which a normal layover absorbs.
At 1,660 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 78.9% on time across 712 flights, 4 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 4 points of difference.
One caution: this is a thin sample. 712 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 SEA to DFW
Put together: treat all of this as provisional. 712 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 75.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 696 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to DFW, every carrier
- Delta on DFW to SEA, the return leg
- Alaska Airlines on SEA to DFW78.9%
- American Airlines on SEA to DFW77.6%
- Delta Air Lines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Dallas/Fort Worth International (DFW) delay statistics
- The best time of day to fly, according to 7.04 million flight records
- Connecting flights: how much buffer the data says you need
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.