Route reliability record
DTW→PHL
Detroit to Philadelphia
- Flights
- 2,952
- Period
- July 2025 to June 2026
- Distance
- 453 mi
- Carriers
- 7
This route lands a B, about a point 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 80.1% 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
78.5%
Arrivals under 15 minutes late, of 2,859 completed flights
Avg delay
86 min
Across delayed arrivals only, not all flights
Cancelled
2.95%
National rate is 1.81%
Best carrier
Delta
80.1% on time across 1,557 flights
These figures cover 2,952 flights between July 2025 and June 2026. Beyond the headline rate, 9.7% 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 DTW to PHL
The two carriers here are closely matched: half a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,557 | 80.1% | 77 min | 2.06% | B |
| PSA Airlines | 846 | 79.5% | 91 min | 5.20% | B− |
| Spirit Airlinesthin sample | 132 | 78.8% | 79 min | 0.00% | B+ |
| Republic Airwaysthin sample | 112 | 73.6% | 88 min | 5.36% | C− |
| American Airlinesthin sample | 179 | 72.3% | 129 min | 0.56% | C+ |
| Frontier Airlinesthin sample | 57 | 69.1% | 55 min | 3.51% | C− |
| SkyWest Airlinesthin sample | 69 | 61.5% | 93 min | 2.90% | D |
PSA Airlines cancels 5.2% 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 20 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am677 flights88.1%
- 8am–11am465 flights85.1%
- 11am–2pm331 flights79.2%
- 2pm–5pm622 flights68.5%
- 5pm–8pm421 flights68.4%
- 8pm–5am436 flights80.3%
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 88.1% of the time, against 68.4% for the evening window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 677 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.
December is the weak month at 64.8% on time, against 87.2% 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 83.6% on time and Sunday the weakest at 74.2%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
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 53,000 reported delay minutes.
- 39%Carrier
- 33%Late-arriving aircraft
- 22%National Airspace System
- 6%Extreme weather
The largest share of delay minutes, 39%, 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 53,000 delay minutes reported here. The split is drawn from 52,640 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 88.1% on time here.
Cancellations run at 2.95%, 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. 9.7% 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 79.8% 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 2.95% 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. 2,859 completed flights over 12 months sit behind that.
Common questions
DTW to PHL questions
How often is DTW to PHL 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 21.5% 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 DTW to PHL?
Delta Air Lines leads at 80.1% on time across 1,557 flights. PSA Airlines is at the other end on 79.5%, a gap of half a point. 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 DTW to PHL?
The 5am–8am departure window is the strongest at 88.1% on time. The 5pm–8pm window is the weakest at 68.4%, 20 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 DTW to PHL?
December is the weakest month at 64.8% on time, compared with 87.2% 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
- PHL to DTW — the return legseparate record
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Philadelphia International (PHL) delay statistics
- Delta Air Lines on-time record80.1%
- PSA Airlines on-time record79.5%
- Spirit Airlines on-time record78.8%
- 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. DTW to PHL and PHL to DTW 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.