Flight number record
DL 999
Delta Air Lines · New York to Detroit
- Route
- LGA → DTW
- Departs
- 17:00
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 999, check with Delta Air Lines.
DL 999 sits in the middle of the pack with a C−. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land an hour and a half behind schedule. That rests on 364 flights, with a median arrival 6 minutes early.
Key figures
On time
73.9%
Arrivals under 15 minutes late, of 349 completed flights
Avg delay
92 min
Across delayed arrivals only, not all flights
Cancelled
3.85%
National rate is 1.89%
1 hour+ late
12.3%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. Beyond the headline rate, 12.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 999 flies
DL 999 flies LGA to DTW without a single fixed slot. Its most common scheduled departure was 17:00, used on 81 of 364 flights, with 16:59 (80 flights) and 16:55 (58 flights) next.
- Departs 17:0081 flights22.3%
- Departs 16:5980 flights22.0%
- Departs 16:5558 flights15.9%
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 17:00 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and DL 999 runs 6 points better at 73.9%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
DL 999 next to LGA to DTW
Every carrier on LGA to DTW combined arrived on time 77.3% of the time across 3,861 flights, so DL 999 is 3 points behind it. Delta flew 1,982 flights on the same city pair under all its flight numbers, including this one, and those ran 81.0% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 7 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 999thin sample | 364 | 73.9% | 92 min | 3.85% | C− |
| All Delta Air Lines on LGA–DTW | 1,982 | 81.0% | 87 min | 4.09% | B− |
| All carriers on LGA–DTW | 3,861 | 77.3% | 83 min | 5.23% | B− |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 999 quarter by quarter
DL 999 did not run the same all year. Its best quarter was Jul–Sep 2025 at 83.3% on time and its weakest Oct–Dec 2025 at 64.8%, a swing of 19 points on roughly 73 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 202530 flights83.3%
- Oct–Dec 202591 flights64.8%
- Jan–Mar 202690 flights80.5%
- Apr–Jun 202691 flights70.8%
- Jul–Sep 202662 flights78.2%
Scale runs 55% to 90%.
By weekday, DL 999 did best on Tuesday at 82.0% on time and worst on Monday at 63.3%. Each day rests on about 52 flights, so a gap of 19 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 999 runs when it is late
DL 999 often beats the schedule: 121 of 349 completed flights, 35%, arrived 15 minutes or more early. The 91 late arrivals split 25 under half an hour, 23 between 30 and 60 minutes, and 43 an hour or more.
- 15+ min early121 flights34.7%
- Within 15 min137 flights39.3%
- 15–29 min late25 flights7.2%
- 30–59 min late23 flights6.6%
- 1–2 hours late20 flights5.7%
- 2+ hours late23 flights6.6%
Scale runs 0% to 100%.
Share of 349 completed flights by arrival against schedule.
A late pushback is often recovered here: of 122 departures that left 15 minutes late or more, 43 still arrived on time. 12 flights left on time and still arrived late.
The worst days
Worst days for DL 999
The latest arrival of the period was on 6 August 2026, 6 hours 36 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 6 August 2026 | 6 hours 36 minutes | National Airspace System |
| 14 June 2026 | 5 hours 28 minutes | Carrier |
| 7 December 2025 | 5 hours 17 minutes | National Airspace System |
| 14 December 2025 | 4 hours 54 minutes | Carrier |
| 19 May 2026 | 4 hours 48 minutes | National Airspace System |
Delay causes
Why DL 999 runs late
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 8,403 reported delay minutes.
- 38%Late-arriving aircraft
- 35%National Airspace System
- 27%Carrier
- 0%Security
- 0%Extreme weather
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 8,403 reported delay minutes here, that single category outweighs weather by 38 to one. The split is drawn from 8,403 delay minutes reported on DL 999.
Cancellations run at 3.85%, against 1.89% nationally. That is about one flight in 25 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
12.3% 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.
The 502 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.
Every one of the 364 flights under DL 999 in the data flew LGA to DTW. 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. 364 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 999
For a booking, the cancellation rate is the figure to plan around on DL 999: 3.85% of its 364 scheduled flights did not operate. A late arrival costs an hour and a half, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- LGA to DTW, every carrier and departure
- DTW to LGA, the return direction
- Delta Air Lines 1231 on the same route95.6%
- Delta Air Lines 1078 on the same route88.1%
- Delta Air Lines 1122 on the same route79.8%
- Republic Airways 4598 on the same route63.6%
- Delta Air Lines 1014 on the same route69.3%
- LaGuardia (LGA) delay statistics
- Detroit Metropolitan Wayne County (DTW) 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
- Why the first flight of the morning is statistically safest
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.