Flight number record

DL 3120

Delta Air Lines · Atlanta to Indianapolis

Route: ATL → IND
Departs: 18:59
Flights: 316
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 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 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 316 flights, with a median arrival 5 minutes early.

On time

80.5%

Arrivals under 15 minutes late, of 313 completed flights

Avg delay

73 min

Across delayed arrivals only, not all flights

Cancelled

0.95%

National rate is 1.81%

1 hour+ late

7.0%

National rate is 8.1%

These figures cover 316 flights between July 2025 and June 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.

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 316 flights, with 20:10 (50 flights) and 20:08 (35 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 18:5959 flights18.7%
Departs 20:1050 flights15.8%
Departs 20:0835 flights11.1%

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 18:59 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and DL 3120 runs 12 points better at 80.5%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

DL 3120 next to ATL to IND

Every carrier on ATL to IND combined arrived on time 82.7% of the time across 3,190 flights, so DL 3120 is 2 points behind it. Delta flew 2,711 flights on the same city pair under all its flight numbers, including this one, and those ran 84.0% on time. Across its whole network Delta Air Lines managed 81.6%, close to this flight's figure.

DL 3120 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 3120thin sample	316	80.5%	73 min	0.95%	B+
All Delta Air Lines on ATL–IND	2,711	84.0%	55 min	1.48%	B
All carriers on ATL–IND	3,190	82.7%	57 min	1.35%	B
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	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 79 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 202591 flights83.5%
Oct–Dec 202580 flights79.7%
Jan–Mar 202676 flights73.0%
Apr–Jun 202669 flights85.5%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, DL 3120 did best on Wednesday at 93.0% on time and worst on Tuesday at 72.1%. Each day rests on about 45 flights, so a gap of 21 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 3120 runs late

One category carries most of the weight here. Carrier accounts for 43% of the 4,431 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.

Carrier
43%
Late-arriving aircraft
40%
National Airspace System
14%
Extreme weather
2%

40% 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 4,431 reported delay minutes here, that single category outweighs weather by 19 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 4,431 delay minutes reported on DL 3120.

Cancellations sit at 0.95% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and routes

What a delay on this flight costs

7.0% 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 a little over 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. 316 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 80.5% on time with 0.95% cancelled over 316 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

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.

Key figures