OOSEA→SLC

SkyWest flew 418 of the 4,107 flights on SEA to SLC, about 10% of it. Its 81.3% on time is 2 points worse than the route as a whole, which runs 83.6%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Delta at 87.0% to Frontier at 72.6%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 87.0% of the time; Alaska Airlines manages 79.6%. Sample sizes sit next to every figure, because a two-point gap across 1,372 flights means less than a ten-point one.

5.0% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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.

The 689 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg is a different operation and performs like one: it runs 77.3% on time across 419 flights, 4 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 4 points of difference.

One caution: this is a thin sample. 418 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.