Route reliability record
PHL→DTW
Philadelphia to Detroit
- Flights
- 2,952
- Period
- July 2025 to June 2026
- Distance
- 453 mi
- Carriers
- 7
This route lands a B−, 2 points better than the national rate of 77.6%. About one flight in five arrive 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 2,952 flights, of which Delta Air Lines flew 1,557 at 82.3% on time.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
79.8%
Arrivals under 15 minutes late, of 2,858 completed flights
Avg delay
96 min
Across delayed arrivals only, not all flights
Cancelled
3.05%
National rate is 1.81%
Best carrier
Delta
82.3% on time across 1,557 flights
These figures cover 2,952 flights between July 2025 and June 2026. Beyond the headline rate, 9.3% 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
Which airline is most reliable on PHL to DTW
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 82.3% of the time; PSA Airlines manages 76.3%. Sample sizes sit next to every figure, because a two-point gap across 845 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 133 | 87.9% | 102 min | 0.75% | A+ |
| Delta Air Lines | 1,557 | 82.3% | 105 min | 2.12% | B |
| American Airlinesthin sample | 179 | 79.7% | 72 min | 0.56% | B+ |
| PSA Airlines | 845 | 76.3% | 73 min | 5.80% | B− |
| Republic Airwaysthin sample | 112 | 74.3% | 110 min | 2.68% | C |
| Frontier Airlinesthin sample | 57 | 67.9% | 56 min | 1.75% | C |
| SkyWest Airlinesthin sample | 69 | 67.2% | 223 min | 2.90% | C |
PSA Airlines cancels 5.8% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after 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 22 points, against 6 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am505 flights90.7%
- 8am–11am721 flights84.9%
- 11am–2pm577 flights80.4%
- 2pm–5pm218 flights73.7%
- 5pm–8pm447 flights68.9%
- 8pm–5am484 flights72.6%
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 90.7% of the time, against 68.9% for the evening window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 721 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 23 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.
December is the weak month at 65.6% on time, against 88.7% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. October was the busiest month here, with 282 flights.
Across the week, Tuesday is the strongest day at 87.1% on time and Friday the weakest at 75.6%. 12 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. Late-arriving aircraft accounts for 43% of the 55,000 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.
- 43%Late-arriving aircraft
- 37%Carrier
- 15%National Airspace System
- 5%Extreme weather
- 0%Security
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 55,000 reported delay minutes here, that single category outweighs weather by 9 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 55,173 reported delay minutes.
The largest share of delay minutes, 37%, 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 20,000 of the 55,000 delay minutes reported here.
Cancellations run at 3.05%, against 1.81% nationally. That is roughly 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 actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.3% 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.
At 453 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg runs 78.5% on time across 2,952 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 2,952 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 delay figures matter less here than the 3.05% cancellation rate. A late arrival costs you an hour and a half; 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. 2,858 completed flights over 12 months sit behind that.
Common questions
PHL to DTW questions
How often is PHL to DTW delayed?
About 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 20.2% of the 2,952 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on PHL to DTW?
Delta Air Lines leads at 82.3% on time across 1,557 flights. PSA Airlines is at the other end on 76.3%, a gap of 6 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 PHL to DTW?
The 5am–8am departure window is the strongest at 90.7% on time. The 5pm–8pm window is the weakest at 68.9%, 22 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 December delays on PHL to DTW?
December is the weakest month at 65.6% on time, compared with 88.7% in September. Across the year that is 23 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 PHL — the return legseparate record
- Philadelphia International (PHL) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Spirit Airlines on-time record87.9%
- Delta Air Lines on-time record82.3%
- American Airlines on-time record79.7%
- 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. PHL to DTW and DTW to PHL 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.