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DelayAtlas

Carrier route record

NKATLDTW

Spirit Airlines · Atlanta to Detroit

Flights
672
Period
July 2025 to June 2026
Share of route
14%
Carriers
3
BGRADE

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

Spirit on ATL to DTW lands a B, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 672 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 3,698 at 79.5% on time.

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

Key figures

On time

76.4%

Arrivals under 15 minutes late, of 657 completed flights

Avg delay

81 min

Across delayed arrivals only, not all flights

Cancelled

2.08%

National rate is 1.81%

Whole route

78.0%

Every carrier on ATL to DTW, 4,871 flights

These figures cover 672 flights between July 2025 and June 2026. Beyond the headline rate, 10.5% 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 DTW

Spirit flew 672 of the 4,871 flights on ATL to DTW, about 14% of it. Its 76.4% on time is 2 points worse than the route as a whole, which runs 78.0%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from Delta at 79.5% to Frontier at 69.2%.

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 79.5% of the time; Frontier Airlines manages 69.2%. Sample sizes sit next to every figure, because a two-point gap across 501 flights means less than a ten-point one.

On-time performance by carrier on ATL to DTW
AirlineFlightsOn timeAvg delayCancelledGrade
Delta Air Lines3,69879.5%57 min0.51%B+
Spirit Airlines (this page)67276.4%81 min2.08%B
Frontier Airlines50169.2%71 min1.40%C

Delta 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 28 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am142 flights90.7%
  • 8am–11am101 flights74.2%
  • 11am–2pm98 flights62.5%
  • 2pm–5pm130 flights79.8%
  • 5pm–8pm54 flights86.8%
  • 8pm–5am147 flights66.4%

Scale runs 55% 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 62.5% on time against 90.7% 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 8pm–5am window is the busiest, with 147 flights scheduled in it.

Across the year

Spirit on ATL to DTW through the year

On-time rate by calendar month76J64F55M72AMJ63J78A93S91O86N80D
Darker means more delays. Figures are on-time percentages.September best, March worst

September is the best month on the calendar at 92.5% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. August was the busiest month here, with 87 flights.

Across the week, Wednesday is the strongest day at 81.6% on time and Friday the weakest at 69.6%. 12 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week74.7Mon74.2Tue81.6Wed80.2Thu69.6Fri78.5Sat76.8Sun
Monday: 74.7 percent on time. Tuesday: 74.2 percent on time. Wednesday: 81.6 percent on time. Thursday: 80.2 percent on time. Friday: 69.6 percent on time. Saturday: 78.5 percent on time. Sunday: 76.8 percent on time

Delay causes

Why Spirit runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 43% of the 13,000 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.

  • Late-arriving aircraft
    43%
  • Carrier
    33%
  • National Airspace System
    22%
  • Security
    1%
  • Extreme weather
    1%

43% 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 13,000 reported delay minutes here, that single category outweighs weather by 43 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 12,533 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 90.7% on time here.

Cancellations sit at 2.08% against a national 1.81%, which is ordinary. Diversions add another 0.15%.

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. 10.5% 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 75.0% on time across 677 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. 672 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 DTW

Put together: treat all of this as provisional. 672 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 76.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 657 completed flights over 12 months sit behind that.

Related

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.