Flight number record
DL 343
Delta Air Lines · Washington to Atlanta
- Route
- DCA → ATL
- Departs
- 07:59
- Flights
- 330
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 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 77.6%. When something does go wrong the average delay runs close to two hours. That rests on 330 flights, with a median arrival 12 minutes early.
Set against the rest of the country, DL 343's record is 8 points better than the US average of 77.6%. That gap is worth roughly 80 fewer late arrivals for every thousand flights.
Key figures
On time
85.6%
Arrivals under 15 minutes late, of 319 completed flights
Avg delay
112 min
Across delayed arrivals only, not all flights
Cancelled
3.33%
National rate is 1.81%
1 hour+ late
7.5%
National rate is 8.1%
These figures cover 330 flights between July 2025 and June 2026. The median arrival is 12 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.
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 222 of 330 flights, with 08:00 (99 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 07:59222 flights67.3%
- Departs 08:0099 flights30.0%
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 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 85.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Against the route
DL 343 next to DCA to ATL
Every carrier on DCA to ATL combined arrived on time 78.8% of the time across 6,813 flights, so DL 343 is 7 points ahead of it. Delta flew 3,838 flights on the same city pair under all its flight numbers, including this one, and those ran 80.9% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 4 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 343thin sample | 330 | 85.6% | 112 min | 3.33% | A− |
| All Delta Air Lines on DCA–ATL | 3,838 | 80.9% | 88 min | 2.81% | B |
| All carriers on DCA–ATL | 6,813 | 78.8% | 80 min | 3.54% | B− |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | B |
Across the year
DL 343 quarter by quarter
Quarter by quarter DL 343 held fairly steady: 90.4% in Jul–Sep 2025, 86.1% in Oct–Dec 2025, 82.4% in Jan–Mar 2026 and 83.1% in Apr–Jun 2026. A spread of 8 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202586 flights90.4%
- Oct–Dec 202580 flights86.1%
- Jan–Mar 202679 flights82.4%
- Apr–Jun 202685 flights83.1%
Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.
By weekday, DL 343 did best on Wednesday at 93.8% on time and worst on Monday at 76.1%. Each day rests on about 47 flights, so a gap of 18 points is worth noticing but could still narrow in another year.
Delay causes
Why DL 343 runs late
One category carries most of the weight here. Carrier accounts for 68% of the 5,140 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.
- 68%Carrier
- 22%National Airspace System
- 10%Late-arriving aircraft
- 0%Extreme weather
The largest share of delay minutes, 68%, 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 3,483 of the 5,140 delay minutes reported here. The split is drawn from 5,140 delay minutes reported on DL 343.
Cancellations run at 3.33%, 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
7.5% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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. 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.
The same number turns up on three other city pairs in the data, including IAH to LGA (12), BOS to RDU (4) and SAT to DTW (1), 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. 330 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: 3.33% of its 330 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 route87.2%
- Delta Air Lines 410 on the same route94.9%
- Delta Air Lines 380 on the same route80.8%
- Delta Air Lines 850 on the same route68.2%
- Delta Air Lines 455 on the same route85.4%
- Delta Air Lines 360 on the same route72.9%
- 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.