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Flight Reliability

AS 521 · Alaska Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and AS 521 moved between routes during this period. Numbers below combine all of them, so treat them as background, not a verdict. For a cleaner answer, check the route you are actually flying.

Combined across all its routes

81%
Arrive within 15 minutes
3 min
Average arrival delay
0.9%
Cancelled
5 min early
Median arrival delay

Based on 231 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon82%(34 flights)
  • Tue88%(33 flights)
  • Wed82%(38 flights)
  • Thu81%(37 flights)
  • Fri77%(31 flights)
  • Sat83%(23 flights)
  • Sun76%(33 flights)
On-time by departure window
  • 9 AM–12 PM73%(33 flights)
  • 12–3 PM90%(101 flights)
  • 3–6 PM92%(50 flights)
  • 6–9 PM56%(45 flights)
On-time trend by month
87%
May

Jun 100% → May 87% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 2025100%11
August 202567%12
September 202550%30
November 202594%17
December 202583%12
January 202684%25
February 202679%28
March 202686%28
April 202692%26
May 202687%31
Departures on time
79%
Diverted
0%
Flights flown
229
Months covered
11

Keep nerding

Based on 231 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.