Flight number record
DL 343
Delta Air Lines · Washington to Atlanta
- Route
- DCA → ATL
- Departs
- 07:59
- Flights
- 332
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 343, check with Delta Air Lines.
DL 343 earns an A−. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.3%. When something does go wrong the average delay runs close to two hours. That rests on 332 flights, with a median arrival 13 minutes early.
Set against the rest of the country, DL 343's record is 8 points better than the US average of 77.3%. That gap is worth roughly 84 fewer late arrivals for every thousand flights.
Key figures
On time
85.7%
Arrivals under 15 minutes late, of 322 completed flights
Avg delay
103 min
Across delayed arrivals only, not all flights
Cancelled
3.01%
National rate is 1.89%
1 hour+ late
6.5%
National rate is 8.3%
These figures cover 332 flights between September 2025 and August 2026. The median arrival is 13 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.
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Schedule
When DL 343 flies
DL 343 flies DCA to ATL without a single fixed slot. Its most common scheduled departure was 07:59, used on 180 of 332 flights, with 08:00 (143 flights) next.
- Departs 07:59180 flights54.2%
- Departs 08:00143 flights43.1%
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 07:59 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 343 runs 4 points worse at 85.7%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 343 next to DCA to ATL
Every carrier on DCA to ATL combined arrived on time 77.1% of the time across 6,799 flights, so DL 343 is 9 points ahead of it. Delta flew 3,850 flights on the same city pair under all its flight numbers, including this one, and those ran 79.2% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 5 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 343thin sample | 332 | 85.7% | 103 min | 3.01% | A− |
| All Delta Air Lines on DCA–ATL | 3,850 | 79.2% | 88 min | 2.55% | B |
| All carriers on DCA–ATL | 6,799 | 77.1% | 79 min | 3.60% | B− |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 343 quarter by quarter
Quarter by quarter DL 343 held fairly steady: 86.1% in Oct–Dec 2025, 82.4% in Jan–Mar 2026, 83.1% in Apr–Jun 2026 and 86.2% in Jul–Sep 2026. A spread of 4 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202528 flights—
- Oct–Dec 202580 flights86.1%
- Jan–Mar 202679 flights82.4%
- Apr–Jun 202685 flights83.1%
- Jul–Sep 202660 flights86.2%
Scale runs 75% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, DL 343 ranged from 81.2% on Monday to 92.0% on Thursday. With about 47 flights behind each day, a spread of 11 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late DL 343 runs when it is late
DL 343 often beats the schedule: 137 of 322 completed flights, 43%, arrived 15 minutes or more early. The 46 late arrivals split 13 under half an hour, 12 between 30 and 60 minutes, and 21 an hour or more.
- 15+ min early137 flights42.5%
- Within 15 min139 flights43.2%
- 15–29 min late13 flights4.0%
- 30–59 min late12 flights3.7%
- 1–2 hours late10 flights3.1%
- 2+ hours late11 flights3.4%
Scale runs 0% to 100%.
Share of 322 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 39 departures that left 15 minutes late or more, only 3 made it up before arrival. 10 flights left on time and still arrived late.
The worst days
Worst days for DL 343
The latest arrival of the period was on 11 August 2026, 11 hours 48 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 August 2026 | 11 hours 48 minutes | Carrier |
| 20 April 2026 | 8 hours 36 minutes | Carrier |
| 4 October 2025 | 7 hours 6 minutes | Carrier |
| 18 August 2026 | 4 hours 17 minutes | Late-arriving aircraft |
| 7 December 2025 | 3 hours 16 minutes | National Airspace System |
Delay causes
Why DL 343 runs late
Carrier accounts for 62% of the 4,714 delay minutes carriers reported here, and the remaining four split what is left.
- 62%Carrier
- 25%National Airspace System
- 12%Late-arriving aircraft
- 0%Extreme weather
The largest share of delay minutes, 62%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,944 of the 4,714 delay minutes reported here. The split is drawn from 4,714 delay minutes reported on DL 343.
Cancellations run at 3.01%, against 1.89% nationally. That is roughly 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
6.5% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last close to two hours, which a normal layover absorbs.
The 547 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.
The same number turns up on two other city pairs in the data, including IAH to LGA (12) and BOS to RDU (4), but none flew often enough under DL 343 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DCA to ATL only.
One caution: this is a thin sample. 332 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 343
For a booking, the cancellation rate is the figure to plan around on DL 343: 3.01% of its 332 scheduled flights did not operate. A late arrival costs close to two hours, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- DCA to ATL, every carrier and departure
- ATL to DCA, the return direction
- Delta Air Lines 926 on the same route86.5%
- Delta Air Lines 380 on the same route77.2%
- Delta Air Lines 410 on the same route94.1%
- Delta Air Lines 850 on the same route63.4%
- Delta Air Lines 455 on the same route83.3%
- Delta Air Lines 330 on the same route93.1%
- Ronald Reagan Washington National (DCA) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) 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
- What a cancellation rate actually tells you (and what it hides)
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.