Route
SEA → BOS
Seattle–Tacoma International Airport Boston Logan International Airport
How punctual is this route?
- On-time arrivals
- 75.1%
- Less than 15 minutes late
- Cancelled
- 1.5%
- Of scheduled flights
- Average delay when late
- 68 min
- Flights arriving 15+ minutes late
- Flights tracked
- 2,554
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 38%
- Airline (crew, maintenance, cleaning) 31%
- Late-arriving aircraft 25%
- Extreme weather 6%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Show as table
| Month | On time | Flights |
|---|---|---|
| September 2025 | 67.2% | 229 |
| October 2025 | 72.4% | 227 |
| November 2025 | 82.8% | 164 |
| December 2025 | 86.2% | 161 |
| January 2026 | 86.0% | 129 |
| February 2026 | 80.3% | 129 |
| March 2026 | 86.5% | 172 |
| April 2026 | 76.0% | 172 |
| May 2026 | 83.0% | 254 |
| June 2026 | 70.8% | 278 |
| July 2026 | 66.1% | 317 |
| August 2026 | 66.8% | 322 |
Source: U.S. DOT Bureau of Transportation Statistics on-time data, September 2025 – August 2026. Covers flights operated by reporting U.S. carriers. About our data
Airlines on this route
| Airline | Flights | On time | Cancelled | Avg. delay when late |
|---|---|---|---|---|
| Alaska Airlines | 1,240 | 77.5% | 1.1% | 56 min |
| Delta Air Lines | 1,067 | 79.8% | 1.7% | 76 min |
| JetBlue Airways | 247 | 43.2% | 2.4% | 80 min |
Delay odds by flight
How often each flight number arrived 15 or more minutes late over the last year.
-
AS306
24% late · 365 flights
-
DL459
12% late · 365 flights
-
DL473
17% late · 363 flights
-
AS460
18% late · 359 flights
-
DL474
33% late · 228 flights
-
AS536
23% late · 224 flights
-
B6398
56% late · 165 flights
-
B6198
59% late · 82 flights
-
DL438
44% late · 80 flights
-
AS219
38% late · 70 flights
-
AS214
21% late · 67 flights
-
AS818
48% late · 55 flights
-
AS1505
3% late · 31 flights
-
DL412
10% late · 31 flights
-
AS330
7% late · 28 flights
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