Flight number record
F9 2551
Frontier Airlines · Philadelphia to Atlanta
- Route
- PHL → ATL
- Departs
- 06:30
- Flights
- 314
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s F9 2551, check with Frontier Airlines.
F9 2551 sits in the middle of the pack with a C−. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 314 flights, with a median arrival 6 minutes early.
The national on-time rate over the same period is 77.3%, so F9 2551 runs 4 points behind the country as a whole. Across a thousand flights that is about 43 extra late arrivals.
Key figures
On time
73.0%
Arrivals under 15 minutes late, of 300 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
4.14%
National rate is 1.89%
1 hour+ late
7.7%
National rate is 8.3%
These figures cover 314 flights between September 2025 and August 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.
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Schedule
When F9 2551 flies
F9 2551 flies PHL to ATL without a single fixed slot. Its most common scheduled departure was 06:30, used on 97 of 314 flights, with 05:30 (45 flights) and 05:05 (34 flights) next.
- Departs 06:3097 flights30.9%
- Departs 05:3045 flights14.3%
- Departs 05:0534 flights10.8%
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 06:30 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and F9 2551 runs 16 points worse at 73.0%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
F9 2551 next to PHL to ATL
Every carrier on PHL to ATL combined arrived on time 78.0% of the time across 5,793 flights, so F9 2551 is 5 points behind it. Frontier flew 1,082 flights on the same city pair under all its flight numbers, including this one, and those ran 66.7% on time. Across its whole network Frontier Airlines managed 72.7%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 2551thin sample | 314 | 73.0% | 62 min | 4.14% | C− |
| All Frontier Airlines on PHL–ATL | 1,082 | 66.7% | 71 min | 2.77% | C |
| All carriers on PHL–ATL | 5,793 | 78.0% | 71 min | 3.11% | B− |
| Frontier Airlines, whole network | 213,022 | 72.7% | 84 min | 2.05% | C |
Across the year
F9 2551 quarter by quarter
F9 2551 did not run the same all year. Its best quarter was Jul–Sep 2026 at 85.0% on time and its weakest Jan–Mar 2026 at 65.8%, a swing of 19 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 202517 flights—
- Oct–Dec 202575 flights72.1%
- Jan–Mar 202676 flights65.8%
- Apr–Jun 202684 flights70.7%
- Jul–Sep 202662 flights85.0%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, F9 2551 did best on Wednesday at 85.3% on time and worst on Saturday at 66.7%. Each day rests on about 45 flights, so a gap of 19 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late F9 2551 runs when it is late
F9 2551 often beats the schedule: 117 of 300 completed flights, 39%, arrived 15 minutes or more early. The 81 late arrivals split 26 under half an hour, 32 between 30 and 60 minutes, and 23 an hour or more.
- 15+ min early117 flights39.0%
- Within 15 min102 flights34.0%
- 15–29 min late26 flights8.7%
- 30–59 min late32 flights10.7%
- 1–2 hours late16 flights5.3%
- 2+ hours late7 flights2.3%
Scale runs 0% to 100%.
Share of 300 completed flights by arrival against schedule.
A late pushback is often recovered here: of 43 departures that left 15 minutes late or more, 14 still arrived on time. In the other direction, 52 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at ATL.
The worst days
Worst days for F9 2551
The latest arrival of the period was on 27 October 2025, 17 hours 16 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On four of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 27 October 2025 | 17 hours 16 minutes | Late-arriving aircraft |
| 10 July 2026 | 2 hours 40 minutes | Carrier |
| 6 January 2026 | 2 hours 33 minutes | Carrier |
| 2 January 2026 | 2 hours 27 minutes | Carrier |
| 30 November 2025 | 2 hours 14 minutes | Carrier |
Delay causes
Why F9 2551 runs late
National Airspace System accounts for 44% of the 5,007 delay minutes carriers reported here, and the remaining four split what is left.
- 44%National Airspace System
- 30%Carrier
- 23%Late-arriving aircraft
- 3%Extreme weather
44% 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 2,222 minutes out of 5,007, against a national NAS share of 21%. The split is drawn from 5,007 delay minutes reported on F9 2551.
Cancellations run at 4.14%, against 1.89% nationally. That is about one flight in 25 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
7.7% 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 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.
Every one of the 314 flights under F9 2551 in the data flew PHL to ATL. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 314 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 F9 2551
For a booking, the cancellation rate is the figure to plan around on F9 2551: 4.14% of its 314 scheduled flights did not operate. A late arrival costs about an hour, but a cancellation costs the day, so leave a later option open.
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 route85.8%
- Delta Air Lines 2270 on the same route87.3%
- Delta Air Lines 1180 on the same route85.0%
- Delta Air Lines 1269 on the same route90.4%
- Delta Air Lines 1100 on the same route83.9%
- Delta Air Lines 1169 on the same route77.9%
- Philadelphia International (PHL) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Frontier Airlines on-time record
- Every Frontier Airlines 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 Frontier Airlines’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.