Flight number record
F9 2779
Frontier Airlines · Atlanta to Chicago
- Route
- ATL → MDW
- Departs
- 21:15
- Flights
- 294
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s F9 2779, check with Frontier Airlines.
F9 2779 draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is close to two hours behind schedule. Build slack into anything you connect to. That rests on 294 flights, with a median arrival 5 minutes late.
The national on-time rate over the same period is 77.6%, so F9 2779 runs 18 points behind the country as a whole. Across a thousand flights that is about 176 extra late arrivals.
Key figures
On time
60.0%
Arrivals under 15 minutes late, of 285 completed flights
Avg delay
105 min
Across delayed arrivals only, not all flights
Cancelled
2.04%
National rate is 1.81%
1 hour+ late
21.4%
National rate is 8.1%
These figures cover 294 flights between July 2025 and June 2026. Beyond the headline rate, 21.4% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Schedule
When F9 2779 flies
F9 2779 flies ATL to MDW without a single fixed slot. Its most common scheduled departure was 21:15, used on 57 of 294 flights, with 21:10 (36 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 21:1557 flights19.4%
- Departs 21:1036 flights12.2%
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 21:15 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and F9 2779 runs 11 points worse at 60.0%. 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
F9 2779 next to ATL to MDW
Every carrier on ATL to MDW combined arrived on time 76.3% of the time across 3,527 flights, so F9 2779 is 16 points behind it. Frontier flew 599 flights on the same city pair under all its flight numbers, including this one, and those ran 65.2% on time. Across its whole network Frontier Airlines managed 73.2%, which this flight trails by 13 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 2779thin sample | 294 | 60.0% | 105 min | 2.04% | D |
| All Frontier Airlines on ATL–MDW | 599 | 65.2% | 97 min | 1.50% | C |
| All carriers on ATL–MDW | 3,527 | 76.3% | 66 min | 1.84% | B |
| Frontier Airlines, whole network | 205,332 | 73.2% | 84 min | 1.85% | C |
Across the year
F9 2779 quarter by quarter
F9 2779 did not run the same all year. Its best quarter was Apr–Jun 2026 at 69.8% on time and its weakest Jan–Mar 2026 at 53.0%, a swing of 17 points on roughly 74 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 202565 flights53.1%
- Oct–Dec 202570 flights60.9%
- Jan–Mar 202669 flights53.0%
- Apr–Jun 202690 flights69.8%
Scale runs 45% to 75%. Rows with fewer than 30 flights show a dash.
By weekday, F9 2779 did best on Friday at 70.0% on time and worst on Monday at 46.9%. Each day rests on about 42 flights, so a gap of 23 points is worth noticing but could still narrow in another year.
Delay causes
Why F9 2779 runs late
One category carries most of the weight here. Late-arriving aircraft accounts for 59% of the 12,000 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.
- 59%Late-arriving aircraft
- 30%Carrier
- 11%National Airspace System
- 0%Extreme weather
59% 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 12,000 reported delay minutes here, that single category outweighs weather by 59 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 11,920 delay minutes reported on F9 2779.
Cancellations sit at 2.04% against a national 1.81%, which is ordinary. Diversions add another 1.02%.
Connections and routes
What a delay on this flight costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 21.4% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 591 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.
Every one of the 294 flights under F9 2779 in the data flew ATL to MDW. 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. 294 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 2779
For a booking, F9 2779 is a flight to put a long connection behind. 21.4% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.
Related
Where to go next
- ATL to MDW, every carrier and departure
- MDW to ATL, the return direction
- Delta Air Lines 1076 on the same route75.8%
- Delta Air Lines 1063 on the same route86.7%
- Delta Air Lines 2417 on the same route87.9%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Chicago Midway International (MDW) 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
- Why the first flight of the morning is statistically safest
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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.