Flight number record

DL 1509

Delta Air Lines · Houston to Atlanta

Route: HOU → ATL
Departs: 11:09
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1509, check with Delta Air Lines.

DL 1509 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 a little over an hour. That rests on 365 flights, with a median arrival 11 minutes early.

Set against the rest of the country, DL 1509's record is 11 points better than the US average of 77.6%. That gap is worth roughly 108 fewer late arrivals for every thousand flights.

On time

88.4%

Arrivals under 15 minutes late, of 354 completed flights

Avg delay

70 min

Across delayed arrivals only, not all flights

Cancelled

2.74%

National rate is 1.81%

1 hour+ late

4.8%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 11 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 1509 flies

DL 1509 flies HOU to ATL without a single fixed slot. Its most common scheduled departure was 11:09, used on 38 of 365 flights. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 11:0938 flights10.4%

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 11:09 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and DL 1509 runs 10 points better at 88.4%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

DL 1509 next to HOU to ATL

Every carrier on HOU to ATL combined arrived on time 79.8% of the time across 2,917 flights, so DL 1509 is 9 points ahead of it. Delta flew 1,416 flights on the same city pair under all its flight numbers, including this one, and those ran 84.9% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 7 points.

DL 1509 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1509	365	88.4%	70 min	2.74%	A
All Delta Air Lines on HOU–ATL	1,416	84.9%	97 min	1.77%	B
All carriers on HOU–ATL	2,917	79.8%	66 min	1.13%	B
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1509 quarter by quarter

Quarter by quarter DL 1509 held fairly steady: 88.0% in Jul–Sep 2025, 88.9% in Oct–Dec 2025, 87.1% in Jan–Mar 2026 and 89.7% in Apr–Jun 2026. A spread of 3 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights88.0%
Oct–Dec 202592 flights88.9%
Jan–Mar 202690 flights87.1%
Apr–Jun 202691 flights89.7%

Scale runs 80% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1509 did best on Monday at 96.0% on time and worst on Saturday at 82.0%. Each day rests on about 52 flights, so a gap of 14 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 1509 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 50% of the 2,877 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.

Late-arriving aircraft
50%
Carrier
43%
National Airspace System
7%

50% 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 2,877 reported delay minutes here, that single category outweighs weather by 50 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 2,877 delay minutes reported on DL 1509.

Cancellations run at 2.74%, against 1.81% nationally. That is roughly one flight in 40 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 4.8% 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 696 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.

DL 1509 is not only a HOU to ATL flight. It also flew ATL to HOU (365 flights, 88.7% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.

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.

Other routes flown as DL 1509
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
ATL to HOU	365	88.7%	52 min	3.01%	A−

What to do with this

Booking DL 1509

For a booking, the cancellation rate is the figure to plan around on DL 1509: 2.74% of its 365 scheduled flights did not operate. A late arrival costs a little over an hour, but a cancellation costs the day, so leave a later option open.

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