Route reliability record
MSO→DEN
Missoula to Denver
- Flights
- 1,198
- Period
- September 2025 to August 2026
- Distance
- 679 mi
- Carriers
- 3
This route lands a B+, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That rests on 1,198 MSO to DEN flights, of which United Airlines flew 717 at 83.1% on time.
Best time to fly MSO to DEN: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 91.9% of the time and Saturday flights 83.7%, against 81.1% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
81.1%
Arrivals under 15 minutes late, of 1,187 completed flights
Avg delay
94 min
Across delayed arrivals only, not all flights
Cancelled
0.58%
National rate is 1.89%
Best carrier
United
83.1% on time across 717 flights
These figures cover 1,198 flights between September 2025 and August 2026. The median arrival is 6 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
Which airline is most reliable on MSO to DEN
The two carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 8 | 87.5% | 55 min | 0.00% | A+ |
| United Airlines | 717 | 83.1% | 91 min | 0.28% | B+ |
| SkyWest Airlines | 473 | 78.0% | 98 min | 1.06% | B |
No carrier stands out. United tops the table at 83.1%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on MSO to DEN
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.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Best ways to make this trip
The most reliable ways to fly Missoula to Denver
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. MSO → DENMissoula to Denver | United Airlines | 82.9% | 83.1% | 0.28% | 5am–8am, Tue | UA 1436 14:35 |
| 2. MSO → DENMissoula to Denver | SkyWest Airlines | 77.2% | 78.0% | 1.06% | 8am–11am, Sat | — |
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 18 points, against 5 points between the best and worst carrier.
- 5am–8am358 flights91.9%
- 8am–11am117 flights91.5%
- 11am–2pm6 flights—
- 2pm–5pm358 flights74.2%
- 5pm–8pm359 flights73.7%
- 8pm–5am—
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.9% of the time, against 73.7% for the evening window. That is 18 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 359 flights scheduled in it.
Explore
Filter MSO to DEN 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 MSO to DEN, the best departure window is 5am–8am at 91.9% on time and the worst is 5pm–8pm at 73.7%, a wide gap of 18.2 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am91.9%
- 8–11am91.5%
- 11am–2pm—
- 2–5pm74.2%
- 5–8pm73.7%
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 20 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.
August is the worst month at 71.3% on time, 20 points below April, the best at 91.1%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. August was the busiest month here, with 124 flights.
Across the week, Saturday is the strongest day at 83.7% on time and Monday the weakest at 75.7%, a spread of 8 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 21,000 reported delay minutes.
- 37%National Airspace System
- 36%Carrier
- 19%Late-arriving aircraft
- 9%Extreme weather
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 7,493 of the 21,000 delay minutes reported here. The split is drawn from 21,072 reported delay minutes.
37% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 7,757 minutes out of 21,000, against a national NAS share of 21%.
Cancellations are rare at 0.58%, 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
6.8% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, which a normal layover absorbs.
The 679 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.
The return leg runs 81.5% on time across 1,198 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,198 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.
Work out the risk of missing a connection in DEN after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 91.1% on time and August 71.3%, a swing of 20 points. If the dates move at all, move them out of August before you think about anything else. 1,187 completed flights over 12 months sit behind that.
Common questions
MSO to DEN questions
How often is MSO to DEN delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.9% of the 1,198 flights in this analysis, against 22.7% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on MSO to DEN?
United Airlines leads at 83.1% on time across 717 flights. SkyWest Airlines is at the other end on 78.0%, a gap of 5 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 MSO to DEN?
The 5am–8am departure window is the strongest at 91.9% on time. The 5pm–8pm window is the weakest at 73.7%, 18 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 August delays on MSO to DEN?
August is the weakest month at 71.3% on time, compared with 91.1% in April. Across the year that is 20 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
- DEN to MSO — the return legseparate record
- Denver International (DEN) delay statistics
- United Airlines on MSO to DEN83.1%
- SkyWest Airlines on MSO to DEN78.0%
- MSO to SLC, a related route91.2%
- PHX to DEN, a related route76.7%
- SLC to DEN, a related route79.0%
- Frontier Airlines on-time record87.5%
- United Airlines on-time record83.1%
- SkyWest Airlines on-time record78.0%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. MSO to DEN and DEN to MSO are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed MSO to DEN’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
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.