Flight number record
DL 3120
Delta Air Lines · Atlanta to Indianapolis
- Route
- ATL → IND
- Departs
- 18:59
- Flights
- 267
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 3120, check with Delta Air Lines.
DL 3120 lands a B, 3 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 267 flights, with a median arrival 5 minutes early.
Key figures
On time
79.9%
Arrivals under 15 minutes late, of 264 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
1.12%
National rate is 1.89%
1 hour+ late
6.4%
National rate is 8.3%
These figures cover 267 flights between September 2025 and August 2026. The median arrival is 5 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 3120 flies
DL 3120 flies ATL to IND without a single fixed slot. Its most common scheduled departure was 18:59, used on 59 of 267 flights, with 20:10 (29 flights) next.
- Departs 18:5959 flights22.1%
- Departs 20:1029 flights10.9%
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 18:59 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and DL 3120 runs 12 points better at 79.9%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
DL 3120 next to ATL to IND
Every carrier on ATL to IND combined arrived on time 81.8% of the time across 3,125 flights, so DL 3120 is 2 points behind it. Delta flew 2,667 flights on the same city pair under all its flight numbers, including this one, and those ran 83.0% on time. Across its whole network Delta Air Lines managed 81.1%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 3120thin sample | 267 | 79.9% | 68 min | 1.12% | B |
| All Delta Air Lines on ATL–IND | 2,667 | 83.0% | 57 min | 1.31% | B |
| All carriers on ATL–IND | 3,125 | 81.8% | 56 min | 1.18% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 3120 quarter by quarter
DL 3120 did not run the same all year. Its best quarter was Apr–Jun 2026 at 85.5% on time and its weakest Jan–Mar 2026 at 73.0%, a swing of 13 points on roughly 89 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 202529 flights—
- Oct–Dec 202580 flights79.7%
- Jan–Mar 202676 flights73.0%
- Apr–Jun 202669 flights85.5%
- Jul–Sep 202613 flights—
Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, DL 3120 did best on Wednesday at 92.1% on time and worst on Thursday at 71.1%. Each day rests on about 38 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 3120 runs when it is late
The 53 late arrivals split 10 under half an hour, 26 between 30 and 60 minutes, and 17 an hour or more.
- 15+ min early44 flights16.7%
- Within 15 min167 flights63.3%
- 15–29 min late10 flights3.8%
- 30–59 min late26 flights9.8%
- 1–2 hours late10 flights3.8%
- 2+ hours late7 flights2.7%
Scale runs 0% to 100%.
Share of 264 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 51 departures that left 15 minutes late or more, only 5 made it up before arrival. 7 flights left on time and still arrived late.
The worst days
Worst days for DL 3120
The latest arrival of the period was on 17 March 2026, 5 hours 4 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 17 March 2026 | 5 hours 4 minutes | Carrier |
| 8 November 2025 | 4 hours 49 minutes | Late-arriving aircraft |
| 13 December 2025 | 4 hours 21 minutes | Carrier |
| 30 November 2025 | 3 hours 17 minutes | Carrier |
| 7 July 2026 | 3 hours 9 minutes | Carrier |
Delay causes
Why DL 3120 runs late
Carrier accounts for 59% of the 3,588 delay minutes carriers reported here, and the remaining four split what is left.
- 59%Carrier
- 28%Late-arriving aircraft
- 13%National Airspace System
- 0%Extreme weather
The largest share of delay minutes, 59%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,131 of the 3,588 delay minutes reported here. The split is drawn from 3,588 delay minutes reported on DL 3120.
Cancellations sit at 1.12% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
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 same number turns up on one other city pair in the data, including IND to ATL (41), but none flew often enough under DL 3120 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ATL to IND only.
One caution: this is a thin sample. 267 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 3120
For a booking, read DL 3120 as 79.9% on time with 1.12% cancelled over 267 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- ATL to IND, every carrier and departure
- IND to ATL, the return direction
- Delta Air Lines 3013 on the same route88.3%
- Delta Air Lines 3134 on the same route81.4%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Indianapolis International (IND) 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
- Worst months to fly in the US, ranked by the data
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.