Flight number record
DL 2104
Delta Air Lines · Austin to Atlanta
- Route
- AUS → ATL
- Departs
- 15:00
- Flights
- 352
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 2104, check with Delta Air Lines.
DL 2104 lands a B, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 352 flights, with a median arrival 6 minutes early.
Key figures
On time
79.1%
Arrivals under 15 minutes late, of 344 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
1.99%
National rate is 1.89%
1 hour+ late
6.4%
National rate is 8.3%
These figures cover 352 flights between September 2025 and August 2026. The median arrival is 6 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Schedule
When DL 2104 flies
DL 2104 flies AUS to ATL without a single fixed slot. Its most common scheduled departure was 15:00, used on 94 of 352 flights, with 14:40 (36 flights) next.
- Departs 15:0094 flights26.7%
- Departs 14:4036 flights10.2%
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 15:00 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 2104 runs 7 points better at 79.1%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
DL 2104 next to AUS to ATL
Every carrier on AUS to ATL combined arrived on time 81.9% of the time across 4,484 flights, so DL 2104 is 3 points behind it. Delta flew 3,162 flights on the same city pair under all its flight numbers, including this one, and those ran 86.1% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 2104thin sample | 352 | 79.1% | 60 min | 1.99% | B |
| All Delta Air Lines on AUS–ATL | 3,162 | 86.1% | 75 min | 1.49% | A |
| All carriers on AUS–ATL | 4,484 | 81.9% | 69 min | 1.27% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 2104 quarter by quarter
DL 2104 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Jul–Sep 2026 at 66.7%, a swing of 27 points on roughly 70 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 flights93.3%
- Oct–Dec 202586 flights81.0%
- Jan–Mar 202683 flights88.6%
- Apr–Jun 202691 flights72.5%
- Jul–Sep 202662 flights66.7%
Scale runs 60% to 100%.
By weekday, DL 2104 did best on Monday at 88.0% on time and worst on Sunday at 67.3%. Each day rests on about 50 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 2104 runs when it is late
DL 2104 often beats the schedule: 94 of 344 completed flights, 27%, arrived 15 minutes or more early. The 72 late arrivals split 23 under half an hour, 27 between 30 and 60 minutes, and 22 an hour or more.
- 15+ min early94 flights27.3%
- Within 15 min178 flights51.7%
- 15–29 min late23 flights6.7%
- 30–59 min late27 flights7.8%
- 1–2 hours late15 flights4.4%
- 2+ hours late7 flights2.0%
Scale runs 0% to 100%.
Share of 344 completed flights by arrival against schedule.
21 of 79 late departures made up the time and arrived on time, 27% of them. 14 flights left on time and still arrived late.
The worst days
Worst days for DL 2104
The latest arrival of the period was on 10 December 2025, 4 hours 29 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across December, November, July and June, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 10 December 2025 | 4 hours 29 minutes | Carrier |
| 8 November 2025 | 4 hours 24 minutes | National Airspace System |
| 7 December 2025 | 3 hours 52 minutes | Late-arriving aircraft |
| 11 July 2026 | 2 hours 55 minutes | National Airspace System |
| 18 June 2026 | 2 hours 41 minutes | Late-arriving aircraft |
Delay causes
Why DL 2104 runs late
Late-arriving aircraft accounts for 43% of the 4,315 delay minutes carriers reported here, and the remaining four split what is left.
- 43%Late-arriving aircraft
- 35%National Airspace System
- 21%Carrier
43% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,315 reported delay minutes here, that single category outweighs weather by 43 to one. The split is drawn from 4,315 delay minutes reported on DL 2104.
Cancellations sit at 1.99% against a national 1.89%, which is ordinary. Diversions add another 0.28%.
Connections and routes
What a delay on this flight costs
6.4% 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 about an hour, which a normal layover absorbs.
The 813 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.
DL 2104 is not only a AUS to ATL flight. It also flew ATL to AUS (328 flights, 85.4% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.
One caution: this is a thin sample. 352 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.
| Also flown as | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| ATL to AUSthin sample | 328 | 85.4% | 48 min | 2.13% | A |
What to do with this
Booking DL 2104
For a booking, read DL 2104 as 79.1% on time with 1.99% cancelled over 352 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- AUS to ATL, every carrier and departure
- ATL to AUS, the return direction
- Delta Air Lines 1344 on the same route96.3%
- Delta Air Lines 1258 on the same route93.3%
- Delta Air Lines 2899 on the same route88.1%
- Delta Air Lines 2976 on the same route92.3%
- Delta Air Lines 1397 on the same route79.8%
- Delta Air Lines 2886 on the same route83.6%
- Austin-Bergstrom International (AUS) 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
- 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.