Flight profile · Alaska Airlines
AS637
Phoenix (PHX) to Seattle (SEA) · scheduled 11:00 AM – 1:59 PM
How AS637 performs
993 operations, July 2023 – July 2026.
AS637 arrived on time 87.6% of the time, against 82.7% for all PHX → SEA flights, so this departure is 4.9 percentage points better than the route as a whole. Against Alaska Airlines’ own flights on this route it is 4.7 points better.
Source: US DOT Bureau of Transportation Statistics · 993 operations, July 2023 – July 2026 · If AS637 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where AS637 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 AS637 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 |
|---|---|---|---|---|---|
| AS637 | 87.6% | 0.81% | -6 min | 3.5% | 993 |
| Alaska Airlines on PHX → SEA | 82.9% | 0.91% | -5 min | 3.7% | 9,134 |
| All PHX → SEA flights | 82.7% | 0.58% | -6 min | 4.3% | 22,315 |
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
Why AS637 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
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for AS637 on PHX → 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 AS637 comes in late, and what that does to the departure.
The aircraft flying AS637 came in 15 or more minutes late on 11% of the departures where its previous flight is known. There are not enough departures in both groups to say how the flight left after a late one and after an on-time one.
Each departure is matched to the flight the same aircraft flew into PHX just before it, using the tail number in the DOT file, 869 of 985 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 |
|---|---|
| AS637 | 11% |
| Network, same turn | 17% |
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 AS637’s aircraft landed 15 or more minutes late is lower than the network’s. There are not enough departures in both groups to compare how it left.
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 PHX late, does that still matter by the time it reaches SEA?
AS637 pushes back an average of 3.8 minutes late and reaches the gate at SEA an average of 0.0 minutes early. The 3.8 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 20.7 minutes on the taxiways at PHX, 3.2 minutes longer than a typical PHX departure in the same hour.
On arrival at SEA, AS637 spends 10.4 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 1.5 minutes shorter 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 35,691 departures from PHX scheduled in the clock hour AS637 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 AS637’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
The hour it leaves PHX
Part of any flight’s record belongs to the clock rather than to the flight. AS637 has one departure time, so this is what that time is worth.
On-time arrival rate. 35,691 departures from PHX are scheduled in the 11 AM–12 PM hour over the period, against 598,518 across the whole day.
AS637 is scheduled out of PHX at 11:00 AM, in the 11 AM–12 PM bank. Departures from PHX in that hour arrive on time 82.6% of the time against 80.3% across the airport’s whole day, so the hour AS637 leaves in is an ordinary one for PHX and explains nothing about its record either way.
The two airport figures cover every departure from PHX 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 AS637 run worse on particular days?
Monday is historically the most reliable day and Tuesday the least, a gap of 6.1 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.
19 min late
against a median of 6 min early
Percentiles over 993 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 |
|---|---|---|---|---|
| DL2444 | Delta Air Lines | 94.6% | 17 min early | 747 |
| DL2419 | Delta Air Lines | 93.1% | 15 min early | 785 |
| AS603 | Alaska Airlines | 87.8% | 8 min early | 760 |
| AS637 this flight | Alaska Airlines | 87.6% | 6 min early | 993 |
| AS645 | Alaska Airlines | 84.8% | 3 min early | 1,079 |
| AS611 | Alaska Airlines | 83.3% | 6 min early | 869 |
| AS739 | Alaska Airlines | 71.0% | 2 min late | 610 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. AS637 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 993 records of AS637 operating PHX → 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