Flight number record
DL 1388
Delta Air Lines · Raleigh to Detroit
- Route
- RDU → DTW
- Departs
- 05:30
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1388, check with Delta Air Lines.
DL 1388 earns an A. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 16 points better than the national rate of 77.3%. When something does go wrong the average delay runs close to two hours. That rests on 365 flights, with a median arrival 15 minutes early.
Set against the rest of the country, DL 1388's record is 16 points better than the US average of 77.3%. That gap is worth roughly 163 fewer late arrivals for every thousand flights.
Key figures
On time
93.6%
Arrivals under 15 minutes late, of 360 completed flights
Avg delay
113 min
Across delayed arrivals only, not all flights
Cancelled
1.37%
National rate is 1.89%
1 hour+ late
3.3%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. The median arrival is 15 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.
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Schedule
When DL 1388 flies
DL 1388 flies RDU to DTW without a single fixed slot. Its most common scheduled departure was 05:30, used on 85 of 365 flights, with 05:38 (60 flights) and 05:33 (57 flights) next.
- Departs 05:3085 flights23.3%
- Departs 05:3860 flights16.4%
- Departs 05:3357 flights15.6%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 05:30 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 1388 runs 4 points better at 93.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 1388 next to RDU to DTW
Every carrier on RDU to DTW combined arrived on time 88.6% of the time across 1,480 flights, so DL 1388 is 5 points ahead of it. Delta flew 1,333 flights on the same city pair under all its flight numbers, including this one, and those ran 88.6% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 13 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1388 | 365 | 93.6% | 113 min | 1.37% | A |
| All Delta Air Lines on RDU–DTW | 1,333 | 88.6% | 85 min | 1.58% | A |
| All carriers on RDU–DTW | 1,480 | 88.6% | 82 min | 1.49% | A |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1388 quarter by quarter
DL 1388 did not run the same all year. Its best quarter was Jul–Sep 2025 at 100.0% on time and its weakest Oct–Dec 2025 at 87.0%, a swing of 13 points on roughly 73 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights100.0%
- Oct–Dec 202592 flights87.0%
- Jan–Mar 202690 flights96.6%
- Apr–Jun 202691 flights93.3%
- Jul–Sep 202662 flights96.7%
Scale runs 80% to 100%.
By weekday, DL 1388 ranged from 88.5% on Friday to 98.1% on Tuesday. With about 52 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late DL 1388 runs when it is late
DL 1388 often beats the schedule: 188 of 360 completed flights, 52%, arrived 15 minutes or more early. When DL 1388 is late it tends to be very late: 12 of its 23 late arrivals were an hour or more behind, and 8 were two hours or more.
- 15+ min early188 flights52.2%
- Within 15 min149 flights41.4%
- 15–29 min late7 flights1.9%
- 30–59 min late4 flights1.1%
- 1–2 hours late4 flights1.1%
- 2+ hours late8 flights2.2%
Scale runs 0% to 100%.
Share of 360 completed flights by arrival against schedule.
5 of 24 late departures made up the time and arrived on time, 21% of them. Only 4 left on time and still arrived late.
The worst days
Worst days for DL 1388
The latest arrival of the period was on 9 December 2025, 5 hours 55 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. Three of the five worst days fell in December 2025.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 9 December 2025 | 5 hours 55 minutes | Late-arriving aircraft |
| 3 April 2026 | 5 hours 41 minutes | Carrier |
| 8 December 2025 | 5 hours 33 minutes | Carrier |
| 8 March 2026 | 4 hours 27 minutes | Carrier |
| 29 December 2025 | 2 hours 40 minutes | National Airspace System |
Delay causes
Why DL 1388 runs late
Carrier accounts for 70% of the 2,604 delay minutes carriers reported here, and the remaining four split what is left.
- 70%Carrier
- 17%National Airspace System
- 14%Late-arriving aircraft
The largest share of delay minutes, 70%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,815 of the 2,604 delay minutes reported here. The split is drawn from 2,604 delay minutes reported on DL 1388.
Cancellations sit at 1.37% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.3% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 501 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.
Every one of the 365 flights under DL 1388 in the data flew RDU to DTW. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 365 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 DL 1388
For a booking, DL 1388 has one of the better records a US domestic flight can show: 93.6% on time and 1.37% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- RDU to DTW, every carrier and departure
- DTW to RDU, the return direction
- Raleigh-Durham International (RDU) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.