Route reliability record
TYS→ATL
Knoxville to Atlanta
- Flights
- 1,724
- Period
- July 2025 to June 2026
- Distance
- 152 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 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 1,724 TYS to ATL flights, with a median arrival 16 minutes early.
Best time to fly TYS to ATL: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 92.6% of the time and Wednesday flights 90.9%, against 87.6% for the route overall.
Set against the rest of the country, this route's record is 10 points better than the US average of 77.6%. That gap is worth roughly 100 fewer late arrivals for every thousand flights.
Key figures
On time
87.6%
Arrivals under 15 minutes late, of 1,690 completed flights
Avg delay
78 min
Across delayed arrivals only, not all flights
Cancelled
1.86%
National rate is 1.81%
Best carrier
Delta
87.6% on time across 1,723 flights
These figures cover 1,724 flights between July 2025 and June 2026. The median arrival is 16 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 TYS to ATL
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 |
|---|---|---|---|---|---|
| Delta Air Lines | 1,723 | 87.6% | 78 min | 1.86% | A |
| Frontier Airlinesthin sample | 1 | 0.0% | 70 min | 0.00% | F+ |
Flight by flight
Flights on TYS to ATL
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 13 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–8am346 flights92.6%
- 8am–11am118 flights90.6%
- 11am–2pm287 flights91.2%
- 2pm–5pm506 flights87.8%
- 5pm–8pm434 flights79.8%
- 8pm–5am33 flights90.3%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.6% of the time, against 79.8% for the evening window. That is 13 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 506 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 18 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 74.4% on time, 18 points below October, the best at 92.8%. 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. October was the busiest month here, with 181 flights.
Across the week, Wednesday is the strongest day at 90.9% on time and Sunday the weakest at 82.4%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 52% of the 16,000 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.
- 52%Late-arriving aircraft
- 29%Carrier
- 18%National Airspace System
- 1%Extreme weather
52% 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 16,000 reported delay minutes here, that single category outweighs weather by 52 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 16,333 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 92.6% on time here.
Cancellations sit at 1.86% against a national 1.81%, which is ordinary. Diversions add another 0.12%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.9% 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.
At 152 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 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 82.8% on time across 1,722 flights, 5 points below 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 5 points of difference.
The sample behind these figures is 1,724 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 ATL 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. October runs 92.8% on time and July 74.4%, a swing of 18 points. If the dates move at all, move them out of July before you think about anything else. 1,690 completed flights over 12 months sit behind that.
Common questions
TYS to ATL questions
How often is TYS to ATL 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 12.4% of the 1,724 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is TYS to ATL compared with the rest of the country?
87.6% of flights arrive on time here against a national 77.6%, a difference of 10 points in its favour. That is worth a A on this site's grading scale.
What time of day has the fewest delays on TYS to ATL?
The 5am–8am departure window is the strongest at 92.6% on time. The 5pm–8pm window is the weakest at 79.8%, 13 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 TYS to ATL?
July is the weakest month at 74.4% on time, compared with 92.8% in October. Across the year that is 18 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
- ATL to TYS — the return legseparate record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- TYS to ORD, a related route68.2%
- LGA to ATL, a related route76.6%
- TYS to DFW, a related route76.5%
- Delta Air Lines on-time record87.6%
- Frontier Airlines on-time record0.0%
- 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. TYS to ATL and ATL to TYS 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.