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Flight Reliability

AS 377 · Alaska Airlines

Atlanta → Seattle (ATL–SEA)92% of its flights flew this route. The rest (MSO–SEA) are included in these numbers.

92
Nerd Approved
WanderNerd Reliability Score
85%
Arrive within 15 minutes
1 min
Average arrival delay
0.3%
Cancelled
8 min early
Median arrival delay

Based on 341 historical flights. Data through May 2026.

What the data says

The 6–9 AM departure wins.

AS 377 departing between 6–9 AM arrived on time 86% of the time, versus 55% between 9 AM–12 PM.

Sunday scaries are real for this one.

AS 377 arrived on time 95% of the time on Wednesdays and just 78% on Sundays. That gap is worth planning around.

A bit ahead of the ATL–SEA route.

AS 377 arrived on time 85% of the time, versus 78% across the ATL–SEA route.

A bit ahead of the Alaska Airlines network.

AS 377 arrived on time 85% of the time, versus 80% across the Alaska Airlines network.

The breakdown

On-time by weekday
  • Mon84%(51 flights)
  • Tue86%(43 flights)
  • Wed95%(39 flights)
  • Thu87%(52 flights)
  • Fri79%(52 flights)
  • Sat87%(52 flights)
  • Sun78%(51 flights)
On-time by departure window
  • 6–9 AM86%(329 flights)
  • 9 AM–12 PM55%(11 flights)
On-time trend by month
90%
May

Jun 73% → May 90% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202573%30
July 202594%31
August 202589%28
September 202595%21
October 202589%27
November 202590%30
December 202574%23
January 202674%31
February 202679%28
March 202674%31
April 202697%29
May 202690%31
Departures on time
85%
Diverted
0%
Flights flown
340
Months covered
12

Same route, other flights

Keep nerding

Based on 341 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.