Carrier route record

DLTUS→SEA

Delta Air Lines · Tucson to Seattle

Flights: 138
Period: July 2025 to June 2026
Share of route: 13%
Carriers: 3

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

Delta on TUS to SEA 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 11 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 2.5 hours. That rests on 138 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 371 at 87.3% on time.

Set against the rest of the country, Delta's TUS to SEA record is 11 points better than the US average of 77.6%. That gap is worth roughly 114 fewer late arrivals for every thousand flights.

On time

89.0%

Arrivals under 15 minutes late, of 136 completed flights

Avg delay

152 min

Across delayed arrivals only, not all flights

Cancelled

1.45%

National rate is 1.81%

Whole route

87.0%

Every carrier on TUS to SEA, 1,065 flights

These figures cover 138 flights between July 2025 and June 2026. The median arrival is 16 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.

Carrier by carrier

Delta against every carrier on TUS to SEA

Delta flew 138 of the 1,065 flights on TUS to SEA, about 13% of it. Its 89.0% on time is 2 points better than the route as a whole, which runs 87.0%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from Delta at 89.0% to Alaska at 86.2%.

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.

On-time performance by carrier on TUS to SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines (this page)thin sample	138	89.0%	152 min	1.45%	A
SkyWest Airlines	371	87.3%	65 min	0.00%	A+
Alaska Airlines	556	86.2%	44 min	0.90%	A+

No carrier stands out. SkyWest tops the table at 87.3%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.

Departure window

When Delta runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 10 points, against about a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am—
8am–11am—
11am–2pm60 flights94.8%
2pm–5pm78 flights84.6%
5pm–8pm—
8pm–5am—

Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.

The best window here is not the first bank but the 11am–2pm slot at 94.8% on time, ahead of 2pm–5pm at 84.6%. 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 2pm–5pm window is the busiest, with 78 flights scheduled in it.

Across the year

Delta on TUS to SEA through the year

Oct–Dec 202512 flights—
Jan–Mar 202690 flights84.1%
Apr–Jun 202636 flights97.2%

Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 89.0% on time across 138 flights.

Split by quarter, Delta on TUS to SEA logged 12 flights in Oct–Dec 2025, 90 flights in Jan–Mar 2026 and 36 flights in Apr–Jun 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 89.0% annual figure is the one to use.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. Carrier accounts for 52% of the 2,274 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
52%
Late-arriving aircraft
46%
National Airspace System
2%

46% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 2,274 reported delay minutes here, that single category outweighs weather by 46 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 2,274 reported delay minutes.

The largest share of delay minutes, 52%, 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 1,174 of the 2,274 delay minutes reported here.

Cancellations sit at 1.45% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

6.6% 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 about 2.5 hours, which a normal layover absorbs.

The 1,215 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.

The return leg is a different operation and performs like one: it runs 83.8% on time across 138 flights, 5 points below 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 5 points of difference.

One caution: this is a thin sample. 138 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 TUS to SEA

Put together: treat all of this as provisional. 138 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 89.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 136 completed flights over 12 months sit behind that.

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.

Key figures