Flight number record
DL 2104
Delta Air Lines · Austin to Atlanta
- Route
- AUS → ATL
- Departs
- 15:00
- Flights
- 352
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 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 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 352 flights, with a median arrival 6 minutes early.
Key figures
On time
79.2%
Arrivals under 15 minutes late, of 346 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
1.42%
National rate is 1.81%
1 hour+ late
4.9%
National rate is 8.1%
These figures cover 352 flights between July 2025 and June 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.
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 93 of 352 flights, with 14:40 (36 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 15:0093 flights26.4%
- Departs 14:4036 flights10.2%
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 15:00 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and DL 2104 runs 7 points better at 79.2%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
Against the route
DL 2104 next to AUS to ATL
Every carrier on AUS to ATL combined arrived on time 82.0% of the time across 4,544 flights, so DL 2104 is 3 points behind it. Delta flew 3,232 flights on the same city pair under all its flight numbers, including this one, and those ran 85.6% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 2104thin sample | 352 | 79.2% | 56 min | 1.42% | B |
| All Delta Air Lines on AUS–ATL | 3,232 | 85.6% | 73 min | 1.49% | A |
| All carriers on AUS–ATL | 4,544 | 82.0% | 68 min | 1.43% | B |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | B |
Across the year
DL 2104 quarter by quarter
DL 2104 did not run the same all year. Its best quarter was Jan–Mar 2026 at 88.6% on time and its weakest Apr–Jun 2026 at 72.5%, a swing of 16 points on roughly 88 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 202592 flights76.1%
- Oct–Dec 202586 flights81.0%
- Jan–Mar 202683 flights88.6%
- Apr–Jun 202691 flights72.5%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
By weekday, DL 2104 did best on Saturday at 84.4% on time and worst on Sunday at 68.0%. Each day rests on about 50 flights, so a gap of 16 points is worth noticing but could still narrow in another year.
Delay causes
Why DL 2104 runs late
One category carries most of the weight here. Late-arriving aircraft accounts for 52% of the 4,037 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.
- 52%Late-arriving aircraft
- 24%National Airspace System
- 21%Carrier
- 2%Extreme weather
52% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 4,037 reported delay minutes here, that single category outweighs weather by 23 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 4,037 delay minutes reported on DL 2104.
Cancellations sit at 1.42% against a national 1.81%, which is ordinary. Diversions add another 0.28%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 4.9% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
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. 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.
DL 2104 is not only a AUS to ATL flight. It also flew ATL to AUS (329 flights, 84.2% 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 | 329 | 84.2% | 48 min | 1.52% | B |
What to do with this
Booking DL 2104
For a booking, read DL 2104 as 79.2% on time with 1.42% 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 1258 on the same route93.9%
- Delta Air Lines 1344 on the same route96.6%
- Delta Air Lines 2976 on the same route89.9%
- Delta Air Lines 2899 on the same route87.8%
- Delta Air Lines 1397 on the same route78.1%
- Delta Air Lines 1491 on the same route74.8%
- 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.