Flight profile · Delta Air Lines
DL1551
Los Angeles (LAX) to Seattle (SEA) · scheduled 7:59 PM – 10:25 PM
How DL1551 performs
796 operations, July 2023 – July 2026.
DL1551 arrived on time 81.2% of the time, against 84.8% for all LAX → SEA flights, so this departure is 3.6 percentage points worse than the route as a whole. Against Delta Air Lines’ own flights on this route it is 6.7 points worse.
Source: US DOT Bureau of Transportation Statistics · 796 operations, July 2023 – July 2026 · If DL1551 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where DL1551 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 |
|---|---|---|---|---|---|
| DL1551 | 81.2% | 0.50% | -12 min | 7.7% | 796 |
| Delta Air Lines on LAX → SEA | 87.9% | 0.41% | -15 min | 4.1% | 6,850 |
| All LAX → SEA flights | 84.8% | 0.84% | -10 min | 4.2% | 23,177 |
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
Why DL1551 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
Share of the delay minutes US DOT attributed to each cause for DL1551 on LAX → SEA. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies DL1551 comes in late, and what that does to the departure.
When the aircraft came in 15 or more minutes late, DL1551 pushed back an average of 32 minutes late; when it came in on time or early, an average of 4 minutes late.
Each departure is matched to the flight the same aircraft flew into LAX just before it, using the tail number in the DOT file, 748 of 792 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 |
|---|---|---|---|
| DL1551 | 23% | 47% | 12% |
| Network, same turn | 23% | 40% | 9% |
The schedule leaves a long gap on the ground, which gives a late aircraft room to catch up before this flight pushes back.
The network row is every flight with a scheduled turn of 90 minutes to 3 hours. How often DL1551’s aircraft landed 15 or more minutes late is about the same as the network’s and, once the aircraft was late, how often DL1551 left 15 or more minutes late is higher than 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 July 2023 – July 2026
From pushback to gate
When it leaves LAX late, does that still matter by the time it reaches SEA?
DL1551 pushes back an average of 13.0 minutes late and reaches the gate at SEA an average of 0.5 minutes late. The 12.4 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. It spends 14.1 minutes on the taxiways at LAX, 4.2 minutes shorter than a typical LAX departure in the same hour.
On arrival at SEA, DL1551 spends 14.2 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 2.4 minutes longer than a typical SEA arrival (11.9 min).
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 SEA. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 30,854 departures from LAX scheduled in the clock hour DL1551 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at SEA (510,187 flights), not just DL1551’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
The hour it leaves LAX
Part of any flight’s record belongs to the clock rather than to the flight. DL1551 has one departure time, so this is what that time is worth.
On-time arrival rate. 30,854 departures from LAX are scheduled in the 7 PM–8 PM hour over the period, against 595,153 across the whole day.
DL1551 is scheduled out of LAX at 7:59 PM, in the 7 PM–8 PM bank. Departures from LAX in that hour arrive on time 78.6% of the time against 81.4% across the airport’s whole day, so the hour DL1551 leaves in is an ordinary one for LAX and explains nothing about its record either way.
The two airport figures cover every departure from LAX 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 · July 2023 – July 2026 · Hours below 120 departures are not scored.
Other routes DL1551 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 |
|---|---|---|---|
| ATL→PNS Atlanta to Pensacola | December 19, 2024 – January 4, 2026 | 26 | — |
| PNS→ATL Pensacola to Atlanta | December 19, 2024 – January 4, 2026 | 19 | — |
| MIA→RDU Miami to Raleigh–Durham | May 7, 2024 – June 6, 2024 | 31 | — |
| JFK→MSY New York to New Orleans | April 9, 2024 – May 6, 2024 | 28 | — |
| MSY→JFK New Orleans to New York | April 9, 2024 – May 6, 2024 | 28 | — |
| IND→MSP Indianapolis to Minneapolis | January 8, 2024 – March 9, 2024 | 62 | — |
Because the same number has served different journeys, the statistics above describe only the route DL1551 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.
43 min late
against a median of 12 min early
Percentiles over 796 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| DL1714 | Delta Air Lines | 93.4% | 18 min early | 980 |
| DL2980 | Delta Air Lines | 93.0% | 19 min early | 604 |
| DL1045 | Delta Air Lines | 87.4% | 13 min early | 922 |
| DL2606 | Delta Air Lines | 87.2% | 13 min early | 785 |
| AS1147 | Alaska Airlines | 86.3% | 9 min early | 699 |
| DL2640 | Delta Air Lines | 84.3% | 13 min early | 750 |
| AS1301 | Alaska Airlines | 82.3% | 7 min early | 1,006 |
| AS1317 | Alaska Airlines | 82.2% | 8 min early | 644 |
| DL1551 this flight | Delta Air Lines | 81.2% | 12 min early | 796 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. DL1551 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 796 records of DL1551 operating LAX → SEA, 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