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Route · BIL → SEA · 2020–2025 BTS data

Billings to Seattle

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), BIL to SEA (Billings to Seattle) ranks #4019 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

84.2%
On-time
+5.2 pts
vs US avg
70 min
Delay when late
1,691
Flights
#4019 of 4927
Corpus placement

Cancelled

1.5%

Best Month

Oct 2021 94%

Worst Month

Feb 2021 59%

Distance

664 mi

Carriers

1

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2022 62 23 1 1 QX
Nov 2022 59 16 1 0 QX
Oct 2022 67 9 0 0 QX
Sep 2022 84 6 0 0 QX
Aug 2022 62 6 0 0 QX
Jul 2022 62 7 0 0 QX
Jun 2022 60 9 0 0 QX
May 2022 62 7 0 0 QX
Apr 2022 56 11 0 0 QX
Mar 2022 62 9 0 0 QX
Feb 2022 56 8 2 1 QX
Jan 2022 62 14 2 0 QX
Dec 2021 60 17 5 1 QX
Nov 2021 60 9 1 2 QX
Oct 2021 62 4 0 0 QX
Sep 2021 67 6 0 0 QX
Aug 2021 93 21 0 0 QX
Jul 2021 93 11 1 0 QX
Jun 2021 90 7 1 0 QX
May 2021 93 12 0 0 QX
Apr 2021 90 9 1 0 QX
Mar 2021 93 7 1 0 QX
Feb 2021 74 30 7 1 QX
Jan 2021 62 10 3 1 QX

BIL–SEA seasonal on-time pattern

Best: September (92.1%) · weakest: December (67.2%)

60%70%80%90%100% JanFebMarAprMayJunJulAugSepOctNovDec 67.2%

Strongest calendar month

September

92.1% on-time · ~76 flights/mo

Busiest calendar month

March

~78 flights/mo avg

Weakest calendar month

December

67.2% on-time · ~61 flights/mo

Cancellation Rate

1.5%

26 of 1,691 flights

Diversion Rate

0.4%

7 of 1,691 flights

Explore origin & destination

On-time and delay data for the airports this route connects.

BIL - Billings

Full on-time, delay-cause, and seasonal performance for Billings, MT.

BIL on-time profile

SEA - Seattle

Full on-time, delay-cause, and seasonal performance for Seattle, WA.

SEA on-time profile

Compare the two airports

See BIL and SEA side by side on delays, cancellations, and reliability.

Compare BIL vs SEA

Origin-hub reliability standing

Mid-pack among BIL departures

From BIL, this corridor sits with 4 other 75–85% on-time routes out of 6 tracked departures, not the hub's reliability leaders (2 at ≥85%) and not the softest ( 0 below 75%). Destination: Seattle · fleet on-time rank #1497 of 4927.

What the Data Says About BIL to SEA

Bureau of Transportation Statistics records show Billings to Seattle (BIL to SEA) running a 84.2% on-time rate over 1,691 tracked flights, on the stronger end of a typical domestic pairing. When flights do run late, the average delay is 69.7 minutes. The 664-mile corridor is served by 1 carrier, and over the last 24 months 1.5% of 1,691 flights were cancelled, 0.4% diverted.

The monthly split is wide on this route: Oct 2021 posted the strongest performance at 94% on-time, while Feb 2021 came in at just 59% - a 34-point swing worth factoring into travel timing.

On the multi-year calendar, BIL–SEA peaks in September at 92.1% on-time while March carries the heaviest traffic (~78 flights per month) ; the softest month is December at 67.2%, a 24.9-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does BIL to SEA rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, BIL to SEA ranks #4019 of 4927 tracked domestic routes by total flights (most flights = #1). That ordinal matches our busiest-routes listing (total_flights DESC). See /methodology#corpus-placement for the exact sort basis.
How often are flights delayed from BIL to SEA? ▼
Flights from Billings to Seattle have a 84.2% on-time rate based on 1,691 flights. The average delay is 69.7 minutes. The best recent month was Oct 2021 with 94% on-time.
What is the cancellation rate for BIL to SEA? ▼
Over the last 24 months, 1.5% of flights on this route were cancelled (26 of 1,691 flights) and 0.4% were diverted.
How far is the flight from BIL to SEA? ▼
The flight distance from Billings (BIL) to Seattle (SEA) is approximately 664 miles. This route is served by 1 carrier.
When is the best time to fly from BIL to SEA? ▼
The best recent month for on-time performance was Oct 2021 (94% on-time). The worst was Feb 2021 (59% on-time). Consider booking during months with historically better performance.

Airports on this route

BIL Airport

Billings
SEA Airport

Seattle
Data source

Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data. Statistics reflect cumulative performance across all available reporting periods.

Read our methodology - how this data is sourced, computed, and verified.

Using BIL–SEA data

BIL–SEA runs 5.2 pts above the national 79% average; the remaining risk is month-to-month swing and carrier mix, not a weak headline rate.

  • Compare BIL and SEA airport profiles: delay causes and top routes differ even on the same corridor. BIL airport
  • If your dates flex, September (92.1% on-time) beats December (67.2%) on this corridor. Seasonal chart
  • 4 other routes post a similar 84.2% on-time rate; compare before you commit to this pairing. Similar routes

On-time rate reflects the BTS historical average across all reporting carriers on this origin–destination pair, not any single flight or booking recommendation.

Data sourced from U.S. Department of Transportation Bureau of Transportation Statistics (BTS) On-Time Performance data. See our methodology for details. Retrieved and formatted by PlainFlights

Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This page aggregates this specific route's on-time performance and monthly trend, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.