Flight profile · Alaska Airlines
AS311
Boston (BOS) to Portland (PDX) · scheduled 7:59 PM – 10:09 AM
How AS311 performs
757 operations, July 2023 – July 2026.
AS311 arrived on time 80.5% of the time, against 74.9% for all BOS → PDX flights, so this departure is 5.6 percentage points better than the route as a whole. Against Alaska Airlines’ own flights on this route it is 2.5 points better.
Source: US DOT Bureau of Transportation Statistics · 757 operations, July 2023 – July 2026 · If AS311 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where AS311 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 AS311 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 |
|---|---|---|---|---|---|
| AS311 | 80.5% | 1.85% | -9 min | 5.7% | 757 |
| Alaska Airlines on BOS → PDX | 78.0% | 1.51% | -8 min | 6.4% | 1,520 |
| All BOS → PDX flights | 74.9% | 1.56% | -6 min | 8.5% | 2,050 |
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
Why AS311 runs late
Where US DOT attributed the delay minutes on this flight.
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding and fueling, all within the carrier’s 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 AS311 on BOS → PDX. 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 AS311 comes in late, and what that does to the departure.
When the aircraft came in 15 or more minutes late, AS311 pushed back an average of 40 minutes late; when it came in on time or early, an average of 3 minutes early.
Each departure is matched to the flight the same aircraft flew into BOS just before it, using the tail number in the DOT file, 735 of 744 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 |
|---|---|---|---|
| AS311 | 25% | 64% | 5% |
| 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 AS311’s aircraft landed 15 or more minutes late is higher than the network’s and, once the aircraft was late, how often AS311 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 BOS late, does that still matter by the time it reaches PDX?
AS311 pushes back an average of 7.9 minutes late and reaches the gate at PDX an average of 1.9 minutes early. The 9.9 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 24.8 minutes on the taxiways at BOS, 3.2 minutes longer than a typical BOS departure in the same hour.
On arrival at PDX, AS311 spends 5.1 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 PDX 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 PDX. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 24,278 departures from BOS scheduled in the clock hour AS311 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at PDX (187,629 flights), not just AS311’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
The hour it leaves BOS
Part of any flight’s record belongs to the clock rather than to the flight. AS311 has one departure time, so this is what that time is worth.
On-time arrival rate. 24,278 departures from BOS are scheduled in the 7 PM–8 PM hour over the period, against 440,893 across the whole day.
AS311 is scheduled out of BOS at 7:59 PM, in the 7 PM–8 PM bank. Departures from BOS in that hour arrive on time 65.1% of the time against 77.2% across the airport’s whole day — the slot alone is worth 12.1 points worse before anything about this particular flight is considered.
The two airport figures cover every departure from BOS 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 AS311 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.
Because the same number has served different journeys, the statistics above describe only the route AS311 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.
38 min late
against a median of 9 min early
Percentiles over 757 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Data and methodology
Calculated by FlyerIntel from 757 records of AS311 operating BOS → PDX, 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
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