Flight number record
DL 1147
Delta Air Lines · Atlanta to Chicago
- Route
- ATL → ORD
- Departs
- 09:00
- Flights
- 360
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1147, check with Delta Air Lines.
DL 1147 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 roughly 45 minutes on average. That is a workable record, not a spotless one. That rests on 360 flights, with a median arrival 3 minutes early.
Key figures
On time
79.2%
Arrivals under 15 minutes late, of 346 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
3.06%
National rate is 1.81%
1 hour+ late
4.6%
National rate is 8.1%
These figures cover 360 flights between July 2025 and June 2026. The median arrival is 3 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 1147 flies
DL 1147 flies ATL to ORD without a single fixed slot. Its most common scheduled departure was 09:00, used on 76 of 360 flights, with 09:05 (45 flights) and 09:08 (40 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 09:0076 flights21.1%
- Departs 09:0545 flights12.5%
- Departs 09:0840 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 09:00 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and DL 1147 runs 5 points worse at 79.2%. 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 1147 next to ATL to ORD
Every carrier on ATL to ORD combined arrived on time 70.6% of the time across 6,406 flights, so DL 1147 is 9 points ahead of it. Delta flew 2,625 flights on the same city pair under all its flight numbers, including this one, and those ran 69.1% 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 1147thin sample | 360 | 79.2% | 47 min | 3.06% | B− |
| All Delta Air Lines on ATL–ORD | 2,625 | 69.1% | 63 min | 2.21% | C |
| All carriers on ATL–ORD | 6,406 | 70.6% | 81 min | 2.34% | C |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | B |
Across the year
DL 1147 quarter by quarter
DL 1147 did not run the same all year. Its best quarter was Jul–Sep 2025 at 92.2% on time and its weakest Oct–Dec 2025 at 66.7%, a swing of 26 points on roughly 90 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 flights92.2%
- Oct–Dec 202592 flights66.7%
- Jan–Mar 202690 flights71.6%
- Apr–Jun 202686 flights85.9%
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, DL 1147 did best on Wednesday at 88.2% on time and worst on Friday at 74.5%. Each day rests on about 51 flights, so a gap of 14 points is worth noticing but could still narrow in another year.
Delay causes
Why DL 1147 runs late
One category carries most of the weight here. National Airspace System accounts for 55% of the 3,356 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.
- 55%National Airspace System
- 39%Carrier
- 5%Late-arriving aircraft
- 1%Extreme weather
55% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 1,858 minutes out of 3,356, against a national NAS share of 21%. The split is drawn from 3,356 delay minutes reported on DL 1147.
Cancellations run at 3.06%, against 1.81% nationally. That is roughly 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
Badly late arrivals are rare here: only 4.6% 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 606 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 1147 is not only a ATL to ORD flight. It also flew ORD to ATL (359 flights, 79.9% 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. 360 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 |
|---|---|---|---|---|---|
| ORD to ATLthin sample | 359 | 79.9% | 72 min | 2.79% | B |
What to do with this
Booking DL 1147
For a booking, the cancellation rate is the figure to plan around on DL 1147: 3.06% of its 360 scheduled flights did not operate. A late arrival costs roughly 45 minutes, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- ATL to ORD, every carrier and departure
- ORD to ATL, the return direction
- Delta Air Lines 2738 on the same route60.6%
- United Airlines 516 on the same route72.9%
- Frontier Airlines 1441 on the same route70.8%
- United Airlines 1046 on the same route58.9%
- Delta Air Lines 2879 on the same route46.8%
- Delta Air Lines 1178 on the same route88.0%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Chicago O'Hare International (ORD) 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.