Flight number record

DL 1535

Delta Air Lines · Phoenix to Salt Lake City

Route: PHX → SLC
Departs: 06:00
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1535, check with Delta Air Lines.

DL 1535 earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 19 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 2.2 hours. That rests on 365 flights, with a median arrival 14 minutes early.

Set against the rest of the country, DL 1535's record is 19 points better than the US average of 77.6%. That gap is worth roughly 194 fewer late arrivals for every thousand flights.

On time

97.0%

Arrivals under 15 minutes late, of 364 completed flights

Avg delay

132 min

Across delayed arrivals only, not all flights

Cancelled

0.27%

National rate is 1.81%

1 hour+ late

1.4%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 14 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 1535 flies

DL 1535 flies PHX to SLC without a single fixed slot. Its most common scheduled departure was 06:00, used on 100 of 365 flights, with 06:05 (90 flights) and 06:55 (62 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 06:00100 flights27.4%
Departs 06:0590 flights24.7%
Departs 06:5562 flights17.0%

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 06:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 1535 runs 8 points better at 97.0%. 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 1535 next to PHX to SLC

Every carrier on PHX to SLC combined arrived on time 83.0% of the time across 5,757 flights, so DL 1535 is 14 points ahead of it. Delta flew 1,708 flights on the same city pair under all its flight numbers, including this one, and those ran 90.4% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 15 points.

DL 1535 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1535	365	97.0%	132 min	0.27%	A+
All Delta Air Lines on PHX–SLC	1,708	90.4%	75 min	0.59%	A+
All carriers on PHX–SLC	5,757	83.0%	61 min	0.56%	B+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1535 quarter by quarter

Quarter by quarter DL 1535 held fairly steady: 96.7% in Jul–Sep 2025, 96.7% in Oct–Dec 2025, 96.7% in Jan–Mar 2026 and 97.8% in Apr–Jun 2026. A spread of about a point is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights96.7%
Oct–Dec 202592 flights96.7%
Jan–Mar 202690 flights96.7%
Apr–Jun 202691 flights97.8%

Scale runs 90% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1535 ranged from 92.3% on Thursday to 100.0% on Tuesday. With about 52 flights behind each day, a spread of 8 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why DL 1535 runs late

One category carries most of the weight here. Carrier accounts for 97% of the 1,450 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
97%
National Airspace System
3%

The largest share of delay minutes, 97%, 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 1,403 of the 1,450 delay minutes reported here. The split is drawn from 1,450 delay minutes reported on DL 1535.

Cancellations are rare at 0.27%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 1.4% 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 507 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 1535 in the data flew PHX to SLC. 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 1535

For a booking, DL 1535 has one of the better records a US domestic flight can show: 97.0% on time and 0.27% cancelled. That is a base rate, not a promise about any single 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