Flight number record
DL 520
Delta Air Lines · Atlanta to New York
- Route
- ATL → LGA
- Departs
- 21:30
- Flights
- 364
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s DL 520, check with Delta Air Lines.
DL 520 sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land about 55 minutes behind schedule. That rests on 364 flights, with a median arrival 2 minutes early.
The national on-time rate over the same period is 77.6%, so DL 520 runs 7 points behind the country as a whole. Across a thousand flights that is about 72 extra late arrivals.
Key figures
On time
70.4%
Arrivals under 15 minutes late, of 348 completed flights
Avg delay
55 min
Across delayed arrivals only, not all flights
Cancelled
3.57%
National rate is 1.81%
1 hour+ late
10.1%
National rate is 8.1%
These figures cover 364 flights between July 2025 and June 2026. Beyond the headline rate, 10.1% 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 520 flies
DL 520 flies ATL to LGA without a single fixed slot. Its most common scheduled departure was 21:30, used on 215 of 364 flights, with 21:00 (127 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 21:30215 flights59.1%
- Departs 21:00127 flights34.9%
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 21:30 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and DL 520 runs level with that at 70.4%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Against the route
DL 520 next to ATL to LGA
Every carrier on ATL to LGA combined arrived on time 73.4% of the time across 8,344 flights, so DL 520 is 3 points behind it. Delta flew 4,936 flights on the same city pair under all its flight numbers, including this one, and those ran 76.7% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 11 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 520thin sample | 364 | 70.4% | 55 min | 3.57% | C− |
| All Delta Air Lines on ATL–LGA | 4,936 | 76.7% | 66 min | 2.96% | B |
| All carriers on ATL–LGA | 8,344 | 73.4% | 75 min | 3.61% | C− |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | B |
Across the year
DL 520 quarter by quarter
Quarter by quarter DL 520 held fairly steady: 73.9% in Jul–Sep 2025, 67.4% in Oct–Dec 2025, 73.3% in Jan–Mar 2026 and 67.0% in Apr–Jun 2026. A spread of 7 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202592 flights73.9%
- Oct–Dec 202591 flights67.4%
- Jan–Mar 202690 flights73.3%
- Apr–Jun 202691 flights67.0%
Scale runs 60% to 80%. Rows with fewer than 30 flights show a dash.
By weekday, DL 520 did best on Friday at 77.1% on time and worst on Monday at 60.0%. Each day rests on about 52 flights, so a gap of 17 points is worth noticing but could still narrow in another year.
Delay causes
Why DL 520 runs late
One category carries most of the weight here. National Airspace System accounts for 47% of the 5,650 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.
- 47%National Airspace System
- 24%Carrier
- 22%Late-arriving aircraft
- 7%Extreme weather
47% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 2,650 minutes out of 5,650, against a national NAS share of 21%. The split is drawn from 5,650 delay minutes reported on DL 520.
Cancellations run at 3.57%, against 1.81% nationally. That is about one flight in 30 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.1% 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.
The 762 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 364 flights under DL 520 in the data flew ATL to LGA. 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 520
For a booking, the cancellation rate is the figure to plan around on DL 520: 3.57% of its 364 scheduled flights did not operate. A late arrival costs about 55 minutes, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- ATL to LGA, every carrier and departure
- LGA to ATL, the return direction
- Frontier Airlines 3288 on the same route40.8%
- Delta Air Lines 997 on the same route66.2%
- Delta Air Lines 513 on the same route88.6%
- Delta Air Lines 371 on the same route85.5%
- Delta Air Lines 434 on the same route62.2%
- Delta Air Lines 557 on the same route86.7%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- LaGuardia (LGA) 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.