Flight number record
DL 939
Delta Air Lines · Los Angeles to New York
- Route
- LAX → JFK
- Departs
- 11:55
- Flights
- 331
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 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, 8 points worse than the national rate of 77.3%. The late ones land an hour and a half behind schedule. That rests on 331 flights, with a median arrival 2 minutes early.
The national on-time rate over the same period is 77.3%, so DL 939 runs 8 points behind the country as a whole. Across a thousand flights that is about 83 extra late arrivals.
Key figures
On time
69.0%
Arrivals under 15 minutes late, of 319 completed flights
Avg delay
89 min
Across delayed arrivals only, not all flights
Cancelled
2.42%
National rate is 1.89%
1 hour+ late
13.8%
National rate is 8.3%
These figures cover 331 flights between September 2025 and August 2026. Beyond the headline rate, 13.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 939 flies
DL 939 flies LAX to JFK without a single fixed slot. Its most common scheduled departure was 11:55, used on 63 of 331 flights, with 13:00 (42 flights) next.
- Departs 11:5563 flights19.0%
- Departs 13:0042 flights12.7%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 11:55 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and DL 939 runs 9 points worse at 69.0%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
DL 939 next to LAX to JFK
Every carrier on LAX to JFK combined arrived on time 77.5% of the time across 10,289 flights, so DL 939 is 9 points behind it. Delta flew 3,367 flights on the same city pair under all its flight numbers, including this one, and those ran 79.4% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 12 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 939thin sample | 331 | 69.0% | 89 min | 2.42% | C |
| All Delta Air Lines on LAX–JFK | 3,367 | 79.4% | 87 min | 2.61% | B |
| All carriers on LAX–JFK | 10,289 | 77.5% | 90 min | 2.90% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 939 quarter by quarter
DL 939 did not run the same all year. Its best quarter was Oct–Dec 2025 at 76.6% on time and its weakest Jul–Sep 2026 at 48.1%, a swing of 28 points on roughly 83 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202526 flights—
- Oct–Dec 202578 flights76.6%
- Jan–Mar 202685 flights67.1%
- Apr–Jun 202680 flights70.0%
- Jul–Sep 202662 flights48.1%
Scale runs 40% to 80%. Rows with fewer than 30 flights show a dash.
By weekday, DL 939 did best on Tuesday at 78.0% on time and worst on Sunday at 62.2%. Each day rests on about 47 flights, so a gap of 16 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 939 runs when it is late
DL 939 often beats the schedule: 100 of 319 completed flights, 31%, arrived 15 minutes or more early. The 99 late arrivals split 21 under half an hour, 34 between 30 and 60 minutes, and 44 an hour or more.
- 15+ min early100 flights31.3%
- Within 15 min120 flights37.6%
- 15–29 min late21 flights6.6%
- 30–59 min late34 flights10.7%
- 1–2 hours late22 flights6.9%
- 2+ hours late22 flights6.9%
Scale runs 0% to 100%.
Share of 319 completed flights by arrival against schedule.
29 of 112 late departures made up the time and arrived on time, 26% of them. In the other direction, 16 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at JFK.
The worst days
Worst days for DL 939
The latest arrival of the period was on 3 August 2026, 10 hours 17 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in August 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 3 August 2026 | 10 hours 17 minutes | Carrier |
| 9 August 2026 | 10 hours 15 minutes | Carrier |
| 27 June 2026 | 6 hours 28 minutes | Late-arriving aircraft |
| 27 May 2026 | 5 hours 17 minutes | Carrier |
| 28 August 2026 | 4 hours 35 minutes | Late-arriving aircraft |
Delay causes
Why DL 939 runs late
Carrier accounts for 46% of the 8,773 delay minutes carriers reported here, and the remaining four split what is left.
- 46%Carrier
- 31%Late-arriving aircraft
- 21%National Airspace System
- 2%Security
- 1%Extreme weather
The largest share of delay minutes, 46%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,069 of the 8,773 delay minutes reported here. The split is drawn from 8,773 delay minutes reported on DL 939.
Cancellations sit at 2.42% against a national 1.89%, which is ordinary. Diversions add another 1.21%.
Connections and routes
What a delay on this flight costs
13.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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 331 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. 331 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 a flight to put a long connection behind. 13.8% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.
Related
Where to go next
- LAX to JFK, every carrier and departure
- JFK to LAX, the return direction
- Delta Air Lines 934 on the same route86.7%
- Delta Air Lines 960 on the same route83.1%
- American Airlines 118 on the same route83.6%
- American Airlines 307 on the same route74.6%
- Delta Air Lines 958 on the same route82.4%
- American Airlines 274 on the same route57.9%
- Los Angeles International (LAX) delay statistics
- John F. Kennedy International (JFK) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- How often a connection fails at the major US hubs
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.