Flight number record
AS 21
Alaska Airlines · New York to Seattle
- Route
- JFK → SEA
- Departs
- 07:00
- Flights
- 358
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s AS 21, check with Alaska Airlines.
AS 21 sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.3%. The late ones land about 50 minutes behind schedule. That rests on 358 flights, with a median arrival right on schedule.
The national on-time rate over the same period is 77.3%, so AS 21 runs 8 points behind the country as a whole. Across a thousand flights that is about 83 extra late arrivals.
Key figures
On time
69.0%
Arrivals under 15 minutes late, of 345 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
3.63%
National rate is 1.89%
1 hour+ late
7.0%
National rate is 8.3%
These figures cover 358 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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Schedule
When AS 21 flies
AS 21 flies JFK to SEA without a single fixed slot. Its most common scheduled departure was 07:00, used on 262 of 358 flights.
- Departs 07:00262 flights73.2%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 07:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and AS 21 runs 20 points worse at 69.0%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
AS 21 next to JFK to SEA
Every carrier on JFK to SEA combined arrived on time 69.5% of the time across 2,906 flights, so AS 21 is about level with it. Alaska flew 1,401 flights on the same city pair under all its flight numbers, including this one, and those ran 68.1% on time. Across its whole network Alaska Airlines managed 79.7%, which this flight trails by 11 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| AS 21thin sample | 358 | 69.0% | 50 min | 3.63% | C− |
| All Alaska Airlines on JFK–SEA | 1,401 | 68.1% | 65 min | 3.35% | C− |
| All carriers on JFK–SEA | 2,906 | 69.5% | 65 min | 3.44% | C− |
| Alaska Airlines, whole network | 309,844 | 79.7% | 52 min | 1.20% | B |
Across the year
AS 21 quarter by quarter
AS 21 did not run the same all year. Its best quarter was Apr–Jun 2026 at 83.1% on time and its weakest Jan–Mar 2026 at 51.2%, a swing of 32 points on roughly 90 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights—
- Oct–Dec 202591 flights60.9%
- Jan–Mar 202685 flights51.2%
- Apr–Jun 202690 flights83.1%
- Jul–Sep 202662 flights75.0%
Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, AS 21 ranged from 64.0% on Sunday to 73.5% on Wednesday. With about 51 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late AS 21 runs when it is late
AS 21 often beats the schedule: 93 of 345 completed flights, 27%, arrived 15 minutes or more early. Most of the lateness is short. 55 of the 107 late arrivals were under half an hour behind, and 24 reached an hour or more.
- 15+ min early93 flights27.0%
- Within 15 min145 flights42.0%
- 15–29 min late55 flights15.9%
- 30–59 min late28 flights8.1%
- 1–2 hours late15 flights4.3%
- 2+ hours late9 flights2.6%
Scale runs 0% to 100%.
Share of 345 completed flights by arrival against schedule.
9 of 44 late departures made up the time and arrived on time, 20% of them. In the other direction, 72 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SEA.
The worst days
Worst days for AS 21
The latest arrival of the period was on 19 July 2026, 6 hours 19 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 19 July 2026 | 6 hours 19 minutes | Carrier |
| 20 May 2026 | 6 hours 7 minutes | Extreme weather |
| 20 January 2026 | 3 hours 41 minutes | Carrier |
| 13 March 2026 | 3 hours 13 minutes | National Airspace System |
| 10 April 2026 | 2 hours 37 minutes | Carrier |
Delay causes
Why AS 21 runs late
National Airspace System accounts for 49% of the 5,385 delay minutes carriers reported here, and the remaining four split what is left.
- 49%National Airspace System
- 35%Carrier
- 8%Extreme weather
- 7%Late-arriving aircraft
- 2%Security
The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,875 of the 5,385 delay minutes reported here. The split is drawn from 5,385 delay minutes reported on AS 21.
Cancellations run at 3.63%, against 1.89% nationally. That is roughly one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and routes
What a delay on this flight costs
7.0% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 50 minutes, which a normal layover absorbs.
At 2,422 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
Every one of the 358 flights under AS 21 in the data flew JFK to SEA. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 358 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking AS 21
For a booking, the cancellation rate is the figure to plan around on AS 21: 3.63% of its 358 scheduled flights did not operate. A late arrival costs about 50 minutes, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- JFK to SEA, every carrier and departure
- SEA to JFK, the return direction
- Delta Air Lines 699 on the same route73.5%
- Delta Air Lines 740 on the same route68.6%
- Alaska Airlines 31 on the same route71.9%
- Delta Air Lines 688 on the same route64.4%
- Alaska Airlines 23 on the same route78.1%
- Alaska Airlines 17 on the same route50.4%
- John F. Kennedy International (JFK) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Alaska Airlines on-time record
- Every Alaska Airlines flight number with a record
- The most and least reliable flight numbers in the US
- What a cancellation rate actually tells you (and what it hides)
A flight number here means Alaska Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.