Route reliability record
ATL→DTW
Atlanta to Detroit
- Flights
- 4,871
- Period
- July 2025 to June 2026
- Distance
- 594 mi
- Carriers
- 3
This route lands a B+, level with the national rate of 77.6%. Roughly one flight in five arrive 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 4,871 flights, of which Delta Air Lines flew 3,698 at 79.5% on time.
Delta Air Lines is the most reliable of the three carriers covered here at 79.5% on time across 3,698 flights.
Key figures
On time
78.0%
Arrivals under 15 minutes late, of 4,825 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
0.82%
National rate is 1.81%
Best carrier
Delta
79.5% on time across 3,698 flights
These figures cover 4,871 flights between July 2025 and June 2026. The median arrival is 4 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
Which airline is most reliable on ATL to DTW
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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 3,698 | 79.5% | 57 min | 0.51% | B+ |
| Spirit Airlines | 672 | 76.4% | 81 min | 2.08% | B |
| Frontier Airlines | 501 | 69.2% | 71 min | 1.40% | 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
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 25 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am753 flights90.9%
- 8am–11am584 flights80.8%
- 11am–2pm913 flights80.4%
- 2pm–5pm845 flights77.8%
- 5pm–8pm761 flights76.4%
- 8pm–5am1,015 flights66.2%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.9% of the time, against 66.2% for the overnight window. That is 25 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 1,015 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 22 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 65.9% on time, 22 points below September, the best at 87.9%. 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. August was the busiest month here, with 447 flights.
Across the week, Wednesday is the strongest day at 85.7% on time and Sunday the weakest at 71.7%. 14 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Carrier accounts for 46% of the 67,000 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.
- 46%Carrier
- 34%Late-arriving aircraft
- 15%National Airspace System
- 5%Extreme weather
- 0%Security
The largest share of delay minutes, 46%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 30,000 of the 67,000 delay minutes reported here. The split is drawn from 66,541 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 90.9% on time here.
Cancellations are rare at 0.82%, 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 actually costs
7.4% 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 are the about an hour kind, which a normal layover absorbs.
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 79.0% on time across 4,881 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.
The sample behind these figures is 4,871 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 this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 87.9% on time and July 65.9%, a swing of 22 points. If the dates move at all, move them out of July before you think about anything else. 4,825 completed flights over 12 months sit behind that.
Common questions
ATL to DTW questions
How often is ATL to DTW delayed?
Roughly one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.0% of the 4,871 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on ATL to DTW?
Delta Air Lines leads at 79.5% on time across 3,698 flights. Frontier Airlines is at the other end on 69.2%, a gap of 10 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on ATL to DTW?
The 5am–8am departure window is the strongest at 90.9% on time. The 8pm–5am window is the weakest at 66.2%, 25 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on ATL to DTW?
July is the weakest month at 65.9% on time, compared with 87.9% in September. Across the year that is 22 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- DTW to ATL — the return legseparate record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Delta Air Lines on-time record79.5%
- Spirit Airlines on-time record76.4%
- Frontier Airlines on-time record69.2%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. ATL to DTW and DTW to ATL are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.