Route reliability record

DTW→BWI

Detroit to Baltimore

Flights: 2,261
Period: July 2025 to June 2026
Distance: 409 mi
Carriers: 5

This route lands a B, 3 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 about an hour on average. That is a workable record, not a spotless one. That rests on 2,261 flights, of which Delta Air Lines flew 1,204 at 81.9% 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.

On time

80.9%

Arrivals under 15 minutes late, of 2,228 completed flights

Avg delay

65 min

Across delayed arrivals only, not all flights

Cancelled

1.33%

National rate is 1.81%

Best carrier

Delta

81.9% on time across 1,204 flights

These figures cover 2,261 flights between July 2025 and June 2026. The median arrival is 7 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 DTW to BWI

The two carriers here are closely matched: 2 points 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.

On-time performance by carrier on DTW to BWI
Airline	Flights	On time	Avg delay	Cancelled	Grade
Republic Airwaysthin sample	14	100.0%	—	7.14%	A−
Spirit Airlinesthin sample	109	82.6%	103 min	0.00%	B+
Delta Air Lines	1,204	81.9%	73 min	1.50%	B
Southwest Airlines	784	79.6%	48 min	1.02%	B
Frontier Airlinesthin sample	150	76.9%	66 min	2.00%	B

No carrier stands out. Delta tops the table at 81.9%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 33 points, against 2 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am542 flights93.3%
8am–11am400 flights82.9%
11am–2pm181 flights78.5%
2pm–5pm560 flights74.7%
5pm–8pm142 flights60.1%
8pm–5am436 flights79.3%

Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 60.1% on time, against 93.3% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 2pm–5pm window is the busiest, with 560 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 20 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.

Darker means more delays. Figures are on-time percentages.October best, December worst

December is the weak month at 70.8% on time, against 90.5% in October. 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 232 flights.

Across the week, Tuesday is the strongest day at 86.4% on time and Monday the weakest at 76.8%. 10 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 43% of the 27,000 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.

Carrier
43%
Late-arriving aircraft
29%
National Airspace System
26%
Extreme weather
2%
Security
0%

The largest share of delay minutes, 43%, 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 12,000 of the 27,000 delay minutes reported here. The split is drawn from 27,469 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 93.3% on time here.

Cancellations sit at 1.33% against a national 1.81%, which is ordinary. Diversions add another 0.13%.

Connections and stage length

What a delay here actually costs

6.2% 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.

At 409 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 81.7% on time across 2,257 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 2,261 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. October runs 90.5% on time and December 70.8%, a swing of 20 points. If the dates move at all, move them out of December before you think about anything else. 2,228 completed flights over 12 months sit behind that.

Common questions

DTW to BWI questions

How often is DTW to BWI 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 19.1% of the 2,261 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on DTW to BWI?

Delta Air Lines leads at 81.9% on time across 1,204 flights. Southwest Airlines is at the other end on 79.6%, a gap of 2 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 DTW to BWI?

The 5am–8am departure window is the strongest at 93.3% on time. The 5pm–8pm window is the weakest at 60.1%, 33 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 BWI?

December is the weakest month at 70.8% on time, compared with 90.5% in October. Across the year that is 20 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. DTW to BWI and BWI 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.

Key figures