Route reliability record
SLC→BIL
Salt Lake City to Billings
- Flights
- 1,074
- Period
- September 2025 to August 2026
- Distance
- 387 mi
- Carriers
- 2
This route earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 1,074 SLC to BIL flights, of which SkyWest Airlines flew 709 at 91.1% on time.
Best time to fly SLC to BIL: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 94.7% of the time and Tuesday flights 91.0%, against 87.2% for the route overall.
Set against the rest of the country, this route's record is 10 points better than the US average of 77.3%. That gap is worth roughly 99 fewer late arrivals for every thousand flights.
Key figures
On time
87.2%
Arrivals under 15 minutes late, of 1,068 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
0.47%
National rate is 1.89%
Best carrier
SkyWest
91.1% on time across 709 flights
These figures cover 1,074 flights between September 2025 and August 2026. The median arrival is 9 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
Which airline is most reliable on SLC to BIL
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 91.1% of the time; Delta Air Lines manages 79.7%. Sample sizes sit next to every figure, because a two-point gap across 365 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 709 | 91.1% | 70 min | 0.56% | A+ |
| Delta Air Lines | 365 | 79.7% | 58 min | 0.27% | B+ |
SkyWest leads Delta by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on SLC to BIL
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Salt Lake City to Billings
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SLC → BILSalt Lake City to Billings | SkyWest Airlines | 90.6% | 91.1% | 0.56% | 8am–11am, Mon | OO 4038 09:25 |
| 2. SLC → BILSalt Lake City to Billings | Delta Air Lines | 79.5% | 79.7% | 0.27% | 8pm–5am, Sat | DL 1340 21:05 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 15 points, against 11 points between the best and worst carrier.
- 5am–8am—
- 8am–11am363 flights94.7%
- 11am–2pm2 flights—
- 2pm–5pm345 flights87.2%
- 5pm–8pm—
- 8pm–5am364 flights79.6%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 94.7% of the time, against 79.6% for the overnight window. That is 15 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 364 flights scheduled in it.
Explore
Filter SLC to BIL by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SLC to BIL, the best departure window is 8am–11am at 94.7% on time and the worst is 8pm–5am at 79.6%, a wide gap of 15.1 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am94.7%
- 11am–2pm—
- 2–5pm87.2%
- 5–8pm—
- 8pm–5am79.6%
best all US flightsScale 60% to 100%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 17 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
February is the weak month at 79.5% on time, against 96.7% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. May was the busiest month here, with 93 flights.
Across the week, Tuesday is the strongest day at 91.0% on time and Sunday the weakest at 82.9%, a spread of 8 points.
Delay causes
Why this route gets delayed
Carrier accounts for 59% of the 8,708 delay minutes carriers reported here, and the remaining four split what is left.
- 59%Carrier
- 20%Late-arriving aircraft
- 17%Extreme weather
- 4%National Airspace System
Extreme weather accounts for 17% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.8 times the usual weather exposure. The split is drawn from 8,708 reported delay minutes.
The largest share of delay minutes, 59%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 5,138 of the 8,708 delay minutes reported here.
Cancellations are rare at 0.47%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.5% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 387 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8am–11am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 91.3% on time across 1,074 flights, 4 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 4 points of difference.
One caution: this is a thin sample. 1,074 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.
Work out the risk of missing a connection in BIL after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 1,074 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 87.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,068 completed flights over 12 months sit behind that.
Common questions
SLC to BIL questions
How often is SLC to BIL delayed?
About one flight in eight arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 12.8% of the 1,074 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on SLC to BIL?
SkyWest Airlines leads at 91.1% on time across 709 flights. Delta Air Lines is at the other end on 79.7%, a gap of 11 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on SLC to BIL?
The 8am–11am departure window is the strongest at 94.7% on time. The 8pm–5am window is the weakest at 79.6%, 15 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are February delays on SLC to BIL?
February is the weakest month at 79.5% on time, compared with 96.7% in September. Across the year that is 17 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- BIL to SLC — the return legseparate record
- Salt Lake City International (SLC) delay statistics
- SkyWest Airlines on SLC to BIL91.1%
- Delta Air Lines on SLC to BIL79.7%
- SLC to DEN, a related route79.0%
- DEN to BIL, a related route80.3%
- SLC to PHX, a related route83.5%
- SkyWest Airlines on-time record91.1%
- Delta Air Lines on-time record79.7%
- Same route, different airline: where the carrier you pick matters most
- The best time of day to fly, according to 7.05 million flight records
Direction matters. SLC to BIL and BIL to SLC are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.