Carrier route record

NKATL→MIA

Spirit Airlines · Atlanta to Miami

Flights: 269
Period: July 2025 to June 2026
Share of route: 4%
Carriers: 6

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Spirit Airlines.

Spirit on ATL to MIA 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 77.6%. The late ones land an hour and a half behind schedule. That rests on 269 flights. The strongest carrier on the route with a full sample, American Airlines, flew 1,527 at 75.2% on time.

American Airlines is the most reliable of the three carriers covered here at 75.2% on time across 1,527 flights.

On time

73.3%

Arrivals under 15 minutes late, of 258 completed flights

Avg delay

99 min

Across delayed arrivals only, not all flights

Cancelled

4.09%

National rate is 1.81%

Whole route

71.0%

Every carrier on ATL to MIA, 6,229 flights

These figures cover 269 flights between July 2025 and June 2026. Beyond the headline rate, 13.2% 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

Spirit against every carrier on ATL to MIA

Spirit flew 269 of the 6,229 flights on ATL to MIA, about 4% of it. Its 73.3% on time is 2 points better than the route as a whole, which runs 71.0%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from American at 75.2% to Republic at 63.6%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. American Airlines arrives on time 75.2% of the time; Frontier Airlines manages 65.3%. Sample sizes sit next to every figure, because a two-point gap across 864 flights means less than a ten-point one.

On-time performance by carrier on ATL to MIA
Airline	Flights	On time	Avg delay	Cancelled	Grade
American Airlines	1,527	75.2%	90 min	0.85%	B+
Envoy Airthin sample	227	74.6%	76 min	1.32%	C
Spirit Airlines (this page)thin 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+

American leads Frontier by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Departure window

When Spirit runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am10 flights—
8am–11am122 flights79.0%
11am–2pm24 flights—
2pm–5pm48 flights77.1%
5pm–8pm53 flights57.1%
8pm–5am12 flights—

Scale runs 50% to 85%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 57.1% on time, against 79.0% for the 8am–11am 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 8am–11am window is the busiest, with 122 flights scheduled in it.

Across the year

Spirit on ATL to MIA through the year

Jul–Sep 202553 flights71.7%
Oct–Dec 202582 flights79.0%
Jan–Mar 202695 flights68.2%
Apr–Jun 202639 flights74.4%

Scale runs 60% to 85%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 73.3% on time across 269 flights.

Spirit on ATL to MIA did not run the same all year. Its best quarter was Oct–Dec 2025 at 79.0% on time and its weakest Jan–Mar 2026 at 68.2%, a swing of 11 points on roughly 67 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.

Across the week, Thursday is the strongest day at 84.6% on time and Monday the weakest at 62.2%. 22 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Spirit runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 6,800 reported delay minutes.

Late-arriving aircraft
35%
National Airspace System
35%
Carrier
30%
Extreme weather
0%

35% 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 6,800 reported delay minutes here, that single category outweighs weather by 35 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 6,800 reported delay minutes.

35% 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 2,347 minutes out of 6,800, against a national NAS share of 21%.

Cancellations run at 4.09%, against 1.81% 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 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. 13.2% 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 runs 74.4% on time across 269 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 269 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 Spirit on ATL to MIA

Put together: the delay figures matter less here than the 4.09% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 258 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures