Carrier route record
AAATL→MIA
American Airlines · Atlanta to Miami
- Flights
- 1,527
- Period
- July 2025 to June 2026
- Share of route
- 25%
- Carriers
- 6
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with American Airlines.
American on ATL to MIA sits in the middle of the pack with a B+. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 1,527 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 3,298 at 70.3% on time.
The US average over the same twelve months is 77.6%, so there is little to separate American on ATL to MIA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
75.2%
Arrivals under 15 minutes late, of 1,511 completed flights
Avg delay
90 min
Across delayed arrivals only, not all flights
Cancelled
0.85%
National rate is 1.81%
Whole route
71.0%
Every carrier on ATL to MIA, 6,229 flights
These figures cover 1,527 flights between July 2025 and June 2026. Beyond the headline rate, 10.7% 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.
Carrier by carrier
American against every carrier on ATL to MIA
American flew 1,527 of the 6,229 flights on ATL to MIA, about 25% of it. Its 75.2% on time is 4 points better than the route as a whole, which runs 71.0%. Ranked by on-time rate it is first of six carriers on the route, where the range runs from American at 75.2% to Republic at 63.6%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines (this page) | 1,527 | 75.2% | 90 min | 0.85% | B+ |
| Envoy Airthin sample | 227 | 74.6% | 76 min | 1.32% | C |
| Spirit Airlinesthin sample | 269 | 73.3% | 99 min | 4.09% | C− |
| Delta Air Lines | 3,298 | 70.3% | 56 min | 1.43% | C |
| Frontier Airlines | 864 | 65.3% | 91 min | 1.62% | C |
| Republic Airwaysthin sample | 44 | 63.6% | 68 min | 0.00% | D+ |
No carrier stands out. Delta tops the table at 70.3%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Departure window
When American runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 40 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am439 flights88.2%
- 8am–11am401 flights80.4%
- 11am–2pm263 flights78.5%
- 2pm–5pm67 flights64.2%
- 5pm–8pm233 flights47.8%
- 8pm–5am124 flights62.6%
Scale runs 40% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 47.8% on time, against 88.2% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 439 flights scheduled in it.
Across the year
American on ATL to MIA through the year
July is the worst month at 62.3% on time, 27 points below September, the best at 88.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. July was the busiest month here, with 155 flights.
Across the week, Wednesday is the strongest day at 82.6% on time and Sunday the weakest at 65.5%. 17 points is a smaller lever than departure hour, but it is free.
Delay causes
Why American runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 53% of the 34,000 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.
- 53%Late-arriving aircraft
- 29%Carrier
- 10%National Airspace System
- 9%Extreme weather
- 0%Security
53% 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 34,000 reported delay minutes here, that single category outweighs weather by 6 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 33,650 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 88.2% on time here.
Cancellations are rare at 0.85%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.7% 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 594 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 return leg is a different operation and performs like one: it runs 67.5% on time across 1,524 flights, 8 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 8 points of difference.
The sample behind these figures is 1,527 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking American on ATL to MIA
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 88.8% on time and July 62.3%, a swing of 27 points. If the dates move at all, move them out of July before you think about anything else. 1,511 completed flights over 12 months sit behind that.
Related
Where to go next
- ATL to MIA, every carrier
- American on MIA to ATL, the return leg
- Envoy Air on ATL to MIA74.6%
- Spirit Airlines on ATL to MIA73.3%
- Delta Air Lines on ATL to MIA70.3%
- Frontier Airlines on ATL to MIA65.3%
- American Airlines network-wide record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Miami International (MIA) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.