Route reliability record
DEN→TYS
Denver to Knoxville
- Flights
- 967
- Period
- July 2025 to June 2026
- Distance
- 1,162 mi
- Carriers
- 5
This route lands a B+, level with the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 967 DEN to TYS flights, with a median arrival 6 minutes early.
Best time to fly DEN to TYS: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 85.3% of the time and Tuesday flights 84.2%, against 78.0% for the route overall.
The US average over the same twelve months is 77.6%, 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
78.0%
Arrivals under 15 minutes late, of 962 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
0.52%
National rate is 1.81%
Best carrier
SkyWest
76.1% on time across 393 flights
These figures cover 967 flights between July 2025 and June 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.
Carrier by carrier
Which airline is most reliable on DEN to TYS
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlinesthin sample | 336 | 81.0% | 48 min | 0.00% | B+ |
| Frontier Airlinesthin sample | 129 | 80.6% | 63 min | 0.00% | B+ |
| SkyWest Airlines | 393 | 76.1% | 64 min | 1.02% | B |
| Southwest Airlinesthin sample | 43 | 74.4% | 42 min | 0.00% | C+ |
| Allegiant Airthin sample | 66 | 70.8% | 174 min | 1.52% | C |
Flight by flight
Flights on DEN to TYS
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.
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 16 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1 flights—
- 8am–11am384 flights85.3%
- 11am–2pm127 flights78.7%
- 2pm–5pm76 flights81.6%
- 5pm–8pm379 flights69.4%
- 8pm–5am—
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 85.3% of the time, against 69.4% for the evening window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 384 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 42 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.
July is the worst month at 51.9% on time, 42 points below November, the best at 93.6%. 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. June was the busiest month here, with 107 flights.
Across the week, Tuesday is the strongest day at 84.2% on time and Thursday the weakest at 73.5%. 11 points is a smaller lever than departure hour, but it is free.
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 14,000 reported delay minutes.
- 37%Late-arriving aircraft
- 37%Carrier
- 22%National Airspace System
- 4%Extreme weather
- 0%Security
37% 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 14,000 reported delay minutes here, that single category outweighs weather by 9 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 14,380 reported delay minutes.
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 5,270 of the 14,000 delay minutes reported here.
Cancellations are rare at 0.52%, below the national 1.81% 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
7.7% 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 an hour, which a normal layover absorbs.
The 1,162 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 84.8% on time across 967 flights, 7 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 7 points of difference.
One caution: this is a thin sample. 967 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 TYS after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 967 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 78.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 962 completed flights over 12 months sit behind that.
Common questions
DEN to TYS questions
How often is DEN to TYS delayed?
Roughly 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 22.0% of the 967 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is DEN to TYS compared with the rest of the country?
78.0% of flights arrive on time here against a national 77.6%, a difference of half a point in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on DEN to TYS?
The 8am–11am departure window is the strongest at 85.3% on time. The 5pm–8pm window is the weakest at 69.4%, 16 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 July delays on DEN to TYS?
July is the weakest month at 51.9% on time, compared with 93.6% in November. Across the year that is 42 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
- TYS to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- United Airlines on DEN to TYS81.0%
- Frontier Airlines on DEN to TYS80.6%
- SkyWest Airlines on DEN to TYS76.1%
- DEN to PHX, a related route75.7%
- ORD to TYS, a related route66.7%
- DEN to SLC, a related route77.5%
- United Airlines on-time record81.0%
- Frontier Airlines on-time record80.6%
- SkyWest Airlines on-time record76.1%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. DEN to TYS and TYS to DEN 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.