DLSLC→SFO

Delta flew 1,706 of the 3,472 flights on SLC to SFO, about 49% of it. Its 67.4% on time is 2 points worse than the route as a whole, which runs 69.0%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from United at 76.6% to Frontier at 66.3%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. United Airlines arrives on time 76.6% of the time; SkyWest Airlines manages 68.8%. Sample sizes sit next to every figure, because a two-point gap across 1,104 flights means less than a ten-point one.

8.4% 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 roughly 50 minutes, which a normal layover absorbs.

The 599 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 78.1% on time across 1,708 flights, 11 points above 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 11 points of difference.

The sample behind these figures is 1,706 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.