Flight profile · Delta Air Lines
DL1187
Detroit (DTW) to Boston (BOS) · scheduled 9:50 PM – 11:52 PM
How DL1187 performs
763 operations, June 2024 – July 2026.
DL1187 arrived on time 69.1% of the time, against 76.7% for all DTW → BOS flights, so this departure is 7.6 percentage points worse than the route as a whole. Against Delta Air Lines’ own flights on this route it is 8.4 points worse.
Source: US DOT Bureau of Transportation Statistics · 763 operations, June 2024 – July 2026 · If DL1187 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where DL1187 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
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Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| DL1187 | 69.1% | 2.10% | -5 min | 11.5% | 763 |
| Delta Air Lines on DTW → BOS | 77.5% | 1.16% | -6 min | 8.6% | 5,258 |
| All DTW → BOS flights | 76.7% | 1.53% | -7 min | 9.5% | 8,286 |
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026
Why DL1187 runs late
Where US DOT attributed the delay minutes on this flight.
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for DL1187 on DTW → BOS. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies DL1187 comes in late, and what that does to the departure.
When the aircraft came in 15 or more minutes late, DL1187 pushed back an average of 59 minutes late; when it came in on time or early, an average of 10 minutes late.
Each departure is matched to the flight the same aircraft flew into DTW just before it, using the tail number in the DOT file, 670 of 747 departures in all. A departure is left out when that flight is unknown, was cancelled or diverted, or the aircraft had sat for more than 12 hours. A flight the airline cancelled never left and is not in the count, and one flown by a substitute aircraft is matched to the aircraft that flew it, not to the one first planned.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late | Left 15+ late after a late inbound | Left 15+ late after an on-time inbound |
|---|---|---|---|
| DL1187 | 27% | 67% | 18% |
| Network, same turn | 17% | 68% | 9% |
The schedule leaves a normal turn: enough time to clean and board if the aircraft is on time, little to spare if it is not.
The network row is every flight with a scheduled turn of 60 to 89 minutes. How often DL1187’s aircraft landed 15 or more minutes late is higher than the network’s and, once the aircraft was late, how often DL1187 left 15 or more minutes late is about the same as the network’s.
More: Which Flight Numbers Pay for a Late Aircraft lists the flight numbers that pass a late aircraft on.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
From pushback to gate
When it leaves DTW late, does that still matter by the time it reaches BOS?
DL1187 pushes back an average of 24.8 minutes late and reaches the gate at BOS an average of 16.3 minutes late. The 8.5 minutes between those two figures are slack the published schedule already carries, which is why a late pushback on this flight does not reliably become a late arrival. Its 17.8 minutes on the taxiways at DTW is about what any departure from the airport in that hour spends.
On arrival at BOS, DL1187 spends 9.1 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is about what any arrival at BOS spends on the ground before reaching the gate.
Departure delay is averaged over every pushback and arrival delay over every completed arrival, so the two counts differ by the flights that never reached BOS. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 35,035 departures from DTW scheduled in the clock hour DL1187 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at BOS (440,886 flights), not just DL1187’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026
The hour it leaves DTW
Part of any flight’s record belongs to the clock rather than to the flight. DL1187 has one departure time, so this is what that time is worth.
On-time arrival rate. 35,035 departures from DTW are scheduled in the 9 PM–10 PM hour over the period, against 388,632 across the whole day.
DL1187 is scheduled out of DTW at 9:50 PM, in the 9 PM–10 PM bank. Departures from DTW in that hour arrive on time 78.1% of the time against 79.6% across the airport’s whole day, so the hour DL1187 leaves in is an ordinary one for DTW and explains nothing about its record either way.
The two airport figures cover every departure from DTW to every destination, so they describe the slot rather than this journey — the like-for-like comparison against the route is above. Hours are scheduled local, and a number whose schedule moved between banks inside the period has no single hour and is not described here at all. Why the hour matters.
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026 · Hours below 120 departures are not scored.
Other routes DL1187 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| MSP→SLC Minneapolis to Salt Lake City | July 5, 2023 – June 6, 2024 | 50 | — |
| ATL→DAB Atlanta to Daytona Beach | March 10, 2024 – May 6, 2024 | 58 | — |
| DAB→ATL Daytona Beach to Atlanta | March 10, 2024 – May 6, 2024 | 58 | — |
| ATL→CAE Atlanta to Columbia | January 13, 2024 – March 9, 2024 | 12 | — |
| CAE→ATL Columbia to Atlanta | January 13, 2024 – March 9, 2024 | 12 | — |
| BNA→ATL Nashville to Atlanta | January 8, 2024 – March 8, 2024 | 47 | — |
| ATL→BNA Atlanta to Nashville | January 15–28, 2024 | 12 | — |
| LGA→MIA New York to Miami | January 1–7, 2024 | 7 | — |
| HPN→ATL White Plains to Atlanta | November 5, 2023 – December 15, 2023 | 41 | — |
| MSY→LAX New Orleans to Los Angeles | October 10–31, 2023 | 12 | — |
| ATL→AUS Atlanta to Austin | October 9–27, 2023 | 11 | — |
| AUS→ATL Austin to Atlanta | October 9–27, 2023 | 11 | — |
| ATL→LIT Atlanta to Little Rock | September 10, 2023 – October 8, 2023 | 29 | — |
| LIT→ATL Little Rock to Atlanta | September 10, 2023 – October 8, 2023 | 29 | — |
| ATL→OKC Atlanta to Oklahoma City | September 5–8, 2023 | 4 | — |
| OKC→ATL Oklahoma City to Atlanta | September 5–8, 2023 | 4 | — |
| LGA→SLC New York to Salt Lake City | July 1–8, 2023 | 2 | — |
Because the same number has served different journeys, the statistics above describe only the route DL1187 currently operates. Blending them would produce an average of two different flights.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
67 min late
against a median of 5 min early
DL1187 has an average that understates its risk: a typical arrival is 5 min early, but the worst tenth are 72 minutes worse than that. If the trip has something unmissable at the end of it, the median is the wrong number to plan against.
Percentiles over 763 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| DL1163 | Delta Air Lines | 90.8% | 13 min early | 782 |
| DL2648 | Delta Air Lines | 84.7% | 8 min early | 1,059 |
| B61336 | JetBlue | 79.1% | 8 min early | 690 |
| DL1171 | Delta Air Lines | 71.3% | 3 min early | 780 |
| DL1187 this flight | Delta Air Lines | 69.1% | 5 min early | 763 |
| B61136 | JetBlue | 60.3% | 1 min late | 639 |
| DL1707 | Delta Air Lines | 60.0% | 7 min late | 638 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. DL1187 is placed in the same ordering rather than left out of it; the rows around it are the most punctual departures on the route, not all of them, so this is a comparison and not a rank. Schedules change; confirm the departure still operates before booking around this.
Data and methodology
Calculated by FlyerIntel from 763 records of DL1187 operating DTW → BOS, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.
Full methodology · Data sources · Report a problem
Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air
Analysis last recomputed