Carrier route record

F9GEG→DEN

Frontier Airlines · Spokane to Denver

Flights: 122
Period: July 2025 to June 2026
Share of route: 6%
Carriers: 4

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.

Frontier on GEG to DEN lands a B+, level with the national rate of 77.6%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by roughly 35 minutes on average. That is a workable record, not a spotless one. That rests on 122 flights. The strongest carrier on the route with a full sample, United Airlines, flew 833 at 85.4% on time.

The US average over the same twelve months is 77.6%, so there is little to separate Frontier on GEG to DEN from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

77.7%

Arrivals under 15 minutes late, of 121 completed flights

Avg delay

36 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.81%

Whole route

83.8%

Every carrier on GEG to DEN, 2,063 flights

These figures cover 122 flights between July 2025 and June 2026. The median arrival is 8 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.

Carrier by carrier

Frontier against every carrier on GEG to DEN

Frontier flew 122 of the 2,063 flights on GEG to DEN, about 6% of it. Its 77.7% on time is 6 points worse than the route as a whole, which runs 83.8%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from SkyWest at 86.7% to Frontier at 77.7%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The two carriers here are closely matched: 3 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.

On-time performance by carrier on GEG to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlinesthin sample	250	86.7%	105 min	0.80%	A+
United Airlines	833	85.4%	83 min	0.36%	A+
Southwest Airlines	858	82.4%	54 min	0.00%	B+
Frontier Airlines (this page)thin sample	122	77.7%	36 min	0.00%	B+

No carrier stands out. United tops the table at 85.4%, 3 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Departure window

When Frontier runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 122 flights.

There are not enough flights in each departure window to split Frontier's GEG to DEN record by time of day without the percentages moving on noise. The headline rate of 77.7% is the reliable figure here.

Across the year

Frontier on GEG to DEN through the year

Jul–Sep 202537 flights70.3%
Oct–Dec 202530 flights83.3%
Jan–Mar 202626 flights—
Apr–Jun 202629 flights—

Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 77.7% on time across 122 flights.

Split by quarter, Frontier on GEG to DEN logged 37 flights in Jul–Sep 2025, 30 flights in Oct–Dec 2025, 26 flights in Jan–Mar 2026 and 29 flights in Apr–Jun 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 77.7% annual figure is the one to use.

Across the week, Sunday is the strongest day at 88.1% on time and Thursday the weakest at 64.1%. 24 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Frontier runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 42% of the 978 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
42%
National Airspace System
35%
Carrier
21%
Extreme weather
2%

42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 978 reported delay minutes here, that single category outweighs weather by 19 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 978 reported delay minutes.

35% 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 344 minutes out of 978, against a national NAS share of 21%.

Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 3.3% land an hour or more behind schedule, against 8.1% 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.

The 836 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 86.1% on time across 122 flights, 8 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 8 points of difference.

One caution: this is a thin sample. 122 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.

What to do with this

Booking Frontier on GEG to DEN

Put together: treat all of this as provisional. 122 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 77.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 121 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures