Flight profile · Alaska Airlines
AS4
Seattle (SEA) to Washington (DCA) · scheduled 8:00 AM – 4:40 PM
How AS4 performs
1,126 operations, July 2023 – July 2026.
AS4 arrived on time 81.4% of the time, against 79.3% for all SEA → DCA flights, so this departure is 2.1 percentage points better than the route as a whole. Against Alaska Airlines’ own flights on this route it is 4.9 points better.
AS4’s scheduled departure has moved during the period FlyerIntel has on file: it typically left around 8:45 AM earlier on, and around 8:00 AM more recently — a 45-minute shift, not the few minutes of day-to-day rounding every published schedule carries. Confirm the current departure time before booking around an older listing.
Source: US DOT Bureau of Transportation Statistics · 1,126 operations, July 2023 – July 2026 · If AS4 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
What stands out
How AS4 compares to other flight numbers, not just to itself.
Which day you fly matters unusually much here, a wider weekday spread than 97% of 1,710 comparable flight numbers.
91.7% on time on a typical Saturday, against 70.7% on a Thursday.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · The one thing about this specific departure that ranks most extreme against every other published flight number, out of everything FlyerIntel checks — shown only when something clears a real statistical bar, not for every flight.
Where AS4 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
Ask for the position of AS4 right now, if receivers on the ground are hearing it. Nothing is requested until you press the button.
Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| AS4 | 81.4% | 0.53% | -9 min | 4.4% | 1,126 |
| Alaska Airlines on SEA → DCA | 76.5% | 0.67% | -5 min | 6.3% | 2,250 |
| All SEA → DCA flights | 79.3% | 0.98% | -7 min | 5.7% | 2,759 |
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
Why AS4 runs late
Where US DOT attributed the delay minutes on this flight.
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for AS4 on SEA → DCA. 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 AS4 comes in late, and what that does to the departure.
When the aircraft came in 15 or more minutes late, AS4 pushed back an average of 9 minutes late; when it came in on time or early, an average of 3 minutes late.
Each departure is matched to the flight the same aircraft flew into SEA just before it, using the tail number in the DOT file, 902 of 1,120 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 |
|---|---|---|---|
| AS4 | 20% | 22% | 14% |
| 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 AS4’s aircraft landed 15 or more minutes late is lower than the network’s and, once the aircraft was late, how often AS4 left 15 or more minutes late is lower 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 SEA late, does that still matter by the time it reaches DCA?
AS4 pushes back an average of 5.9 minutes late and reaches the gate at DCA an average of 2.3 minutes early. The 8.2 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 23.9 minutes on the taxiways at SEA is about what any departure from the airport in that hour spends.
On arrival at DCA, AS4 spends 6.3 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 1.3 minutes shorter than a typical DCA arrival (7.6 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 DCA. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 33,301 departures from SEA scheduled in the clock hour AS4 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at DCA (435,126 flights), not just AS4’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
The hour it leaves SEA
Part of any flight’s record belongs to the clock rather than to the flight. AS4 has one departure time, so this is what that time is worth.
On-time arrival rate. 33,301 departures from SEA are scheduled in the 8 AM–9 AM hour over the period, against 510,205 across the whole day.
AS4 is scheduled out of SEA at 8:00 AM, in the 8 AM–9 AM bank. Departures from SEA in that hour arrive on time 83.7% of the time against 79.1% across the airport’s whole day — the slot alone is worth 4.6 points better before anything about this particular flight is considered.
The two airport figures cover every departure from SEA 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.
By day of week
Does AS4 run worse on particular days?
Saturday is historically the most reliable day and Thursday the least, a gap of 21.0 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Days with fewer than 120 operations are not scored.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
31 min late
against a median of 9 min early
Percentiles over 1,126 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 |
|---|---|---|---|---|
| AS4 this flight | Alaska Airlines | 81.4% | 9 min early | 1,126 |
| AS2 | Alaska Airlines | 71.6% | 2 min early | 1,123 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. AS4 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 1,126 records of AS4 operating SEA → DCA, 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