Flight number record
DL 1100
Delta Air Lines · Philadelphia to Atlanta
- Route
- PHL → ATL
- Departs
- 10:30
- Flights
- 289
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1100, check with Delta Air Lines.
DL 1100 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 45 minutes. That rests on 289 flights, with a median arrival 11 minutes early.
Set against the rest of the country, DL 1100's record is 10 points better than the US average of 77.6%. That gap is worth roughly 100 fewer late arrivals for every thousand flights.
Key figures
On time
87.6%
Arrivals under 15 minutes late, of 282 completed flights
Avg delay
44 min
Across delayed arrivals only, not all flights
Cancelled
2.42%
National rate is 1.81%
1 hour+ late
2.8%
National rate is 8.1%
These figures cover 289 flights between July 2025 and June 2026. The median arrival is 11 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 1100 flies
DL 1100 flies PHL to ATL without a single fixed slot. Its most common scheduled departure was 10:30, used on 73 of 289 flights, with 10:28 (33 flights) and 10:38 (30 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 10:3073 flights25.3%
- Departs 10:2833 flights11.4%
- Departs 10:3830 flights10.4%
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 10:30 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and DL 1100 runs 4 points better at 87.6%. 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 1100 next to PHL to ATL
Every carrier on PHL to ATL combined arrived on time 79.2% of the time across 5,713 flights, so DL 1100 is 8 points ahead of it. Delta flew 3,029 flights on the same city pair under all its flight numbers, including this one, and those ran 84.9% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 6 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1100thin sample | 289 | 87.6% | 44 min | 2.42% | A |
| All Delta Air Lines on PHL–ATL | 3,029 | 84.9% | 59 min | 2.48% | B |
| All carriers on PHL–ATL | 5,713 | 79.2% | 66 min | 2.73% | B |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | B |
Across the year
DL 1100 quarter by quarter
DL 1100 did not run the same all year. Its best quarter was Jul–Sep 2025 at 95.1% on time and its weakest Jan–Mar 2026 at 79.7%, a swing of 15 points on roughly 72 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 202581 flights95.1%
- Oct–Dec 202568 flights84.8%
- Jan–Mar 202683 flights79.7%
- Apr–Jun 202657 flights91.1%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, DL 1100 did best on Wednesday at 95.3% on time and worst on Monday at 76.7%. Each day rests on about 41 flights, so a gap of 19 points is worth noticing but could still narrow in another year.
Delay causes
Why DL 1100 runs late
One category carries most of the weight here. Late-arriving aircraft accounts for 58% of the 1,540 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.
- 58%Late-arriving aircraft
- 23%National Airspace System
- 18%Carrier
- 1%Extreme weather
58% 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 1,540 reported delay minutes here, that single category outweighs weather by 42 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 1,540 delay minutes reported on DL 1100.
Cancellations sit at 2.42% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 2.8% 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 666 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.
The same number turns up on three other city pairs in the data, including ATL to PHL (210), MSP to DFW (31) and ATL to RDU (12), but none flew often enough under DL 1100 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to PHL to ATL only.
One caution: this is a thin sample. 289 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 1100
For a booking, read DL 1100 as 87.6% on time with 2.42% cancelled over 289 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- PHL to ATL, every carrier and departure
- ATL to PHL, the return direction
- Delta Air Lines 1152 on the same route89.9%
- Delta Air Lines 2270 on the same route88.2%
- Delta Air Lines 1180 on the same route88.0%
- Delta Air Lines 1269 on the same route91.4%
- Frontier Airlines 2551 on the same route70.6%
- Delta Air Lines 1169 on the same route75.4%
- Philadelphia International (PHL) 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.