Carrier route record

NKDTW→MIA

Spirit Airlines · Detroit to Miami

Flights: 295
Period: July 2025 to June 2026
Share of route: 16%
Carriers: 6

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

Spirit on DTW to MIA lands a B−, 2 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 295 flights. The strongest carrier on the route with a full sample, American Airlines, flew 394 at 89.4% on time.

The US average over the same twelve months is 77.6%, so there is little to separate Spirit on DTW to MIA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

79.3%

Arrivals under 15 minutes late, of 285 completed flights

Avg delay

66 min

Across delayed arrivals only, not all flights

Cancelled

3.39%

National rate is 1.81%

Whole route

80.5%

Every carrier on DTW to MIA, 1,815 flights

These figures cover 295 flights between July 2025 and June 2026. The median arrival is 5 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.

Carrier by carrier

Spirit against every carrier on DTW to MIA

Spirit flew 295 of the 1,815 flights on DTW to MIA, about 16% of it. Its 79.3% on time is about level with the route as a whole at 80.5%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from American at 89.4% to Frontier at 66.7%. Three 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 89.4% of the time; Delta Air Lines manages 78.4%. Sample sizes sit next to every figure, because a two-point gap across 965 flights means less than a ten-point one.

On-time performance by carrier on DTW to MIA
Airline	Flights	On time	Avg delay	Cancelled	Grade
American Airlines	394	89.4%	102 min	1.27%	A
Envoy Airthin sample	87	79.3%	67 min	0.00%	B+
Spirit Airlines (this page)thin sample	295	79.3%	66 min	3.39%	B−
Delta Air Lines	965	78.4%	55 min	0.93%	B+
Republic Airwaysthin sample	10	70.0%	30 min	0.00%	C+
Frontier Airlinesthin sample	64	66.7%	96 min	1.56%	C

American leads Delta by 11 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 23 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am143 flights91.4%
8am–11am9 flights—
11am–2pm35 flights68.6%
2pm–5pm86 flights72.6%
5pm–8pm22 flights—
8pm–5am—

Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 68.6% on time against 91.4% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 5am–8am window is the busiest, with 143 flights scheduled in it.

Across the year

Spirit on DTW to MIA through the year

Jul–Sep 202577 flights89.6%
Oct–Dec 202573 flights79.7%
Jan–Mar 2026117 flights69.6%
Apr–Jun 202628 flights—

Scale runs 60% to 95%. 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 79.3% on time across 295 flights.

Spirit on DTW to MIA did not run the same all year. Its best quarter was Jul–Sep 2025 at 89.6% on time and its weakest Jan–Mar 2026 at 69.6%, a swing of 20 points on roughly 98 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, Wednesday is the strongest day at 88.9% on time and Friday the weakest at 70.2%. 19 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 3,883 reported delay minutes.

National Airspace System
42%
Carrier
33%
Late-arriving aircraft
25%
Security
0%

42% 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 1,616 minutes out of 3,883, against a national NAS share of 21%. The split is drawn from 3,883 reported delay minutes.

Cancellations run at 3.39%, against 1.81% nationally. That is about one flight in 30 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

7.7% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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 1,145 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 61.7% on time across 292 flights, 18 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 18 points of difference.

One caution: this is a thin sample. 295 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 DTW to MIA

Put together: the delay figures matter less here than the 3.39% cancellation rate. A late arrival costs you about an hour; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 285 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