Flight number record

DL 939

Delta Air Lines · Los Angeles to New York

Route: LAX → JFK
Departs: 13:00
Flights: 322
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 939, check with Delta Air Lines.

DL 939 sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 322 flights, with a median arrival 7 minutes early.

The national on-time rate over the same period is 77.6%, so DL 939 runs 5 points behind the country as a whole. Across a thousand flights that is about 53 extra late arrivals.

On time

72.3%

Arrivals under 15 minutes late, of 318 completed flights

Avg delay

79 min

Across delayed arrivals only, not all flights

Cancelled

1.24%

National rate is 1.81%

1 hour+ late

11.9%

National rate is 8.1%

These figures cover 322 flights between July 2025 and June 2026. Beyond the headline rate, 11.9% 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.

Schedule

When DL 939 flies

DL 939 flies LAX to JFK without a single fixed slot. Its most common scheduled departure was 13:00, used on 65 of 322 flights, with 11:55 (63 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 13:0065 flights20.2%
Departs 11:5563 flights19.6%

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 13:00 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and DL 939 runs 7 points worse at 72.3%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

DL 939 next to LAX to JFK

Every carrier on LAX to JFK combined arrived on time 79.1% of the time across 10,287 flights, so DL 939 is 7 points behind it. Delta flew 3,358 flights on the same city pair under all its flight numbers, including this one, and those ran 81.6% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 9 points.

DL 939 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 939thin sample	322	72.3%	79 min	1.24%	C
All Delta Air Lines on LAX–JFK	3,358	81.6%	93 min	1.79%	B
All carriers on LAX–JFK	10,287	79.1%	92 min	2.04%	B
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 939 quarter by quarter

Quarter by quarter DL 939 held fairly steady: 75.9% in Jul–Sep 2025, 76.6% in Oct–Dec 2025, 67.1% in Jan–Mar 2026 and 70.0% in Apr–Jun 2026. A spread of 10 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202579 flights75.9%
Oct–Dec 202578 flights76.6%
Jan–Mar 202685 flights67.1%
Apr–Jun 202680 flights70.0%

Scale runs 60% to 80%. Rows with fewer than 30 flights show a dash.

By weekday, DL 939 did best on Friday at 81.6% on time and worst on Sunday at 65.2%. Each day rests on about 46 flights, so a gap of 16 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 939 runs late

One category carries most of the weight here. Carrier accounts for 45% of the 6,972 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
45%
National Airspace System
27%
Late-arriving aircraft
25%
Security
2%
Extreme weather
1%

The largest share of delay minutes, 45%, 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 3,165 of the 6,972 delay minutes reported here. The split is drawn from 6,972 delay minutes reported on DL 939.

Cancellations sit at 1.24% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and routes

What a delay on this flight costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.9% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

At 2,475 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.

Every one of the 322 flights under DL 939 in the data flew LAX to JFK. 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. 322 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 939

For a booking, DL 939 is one of the weaker ways to fly LAX to JFK: 7 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.

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