Route reliability record
TYS→ATL
Knoxville to Atlanta
- Flights
- 1,728
- Period
- September 2025 to August 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 11 points better than the national rate of 77.3%. When something does go wrong the average delay runs a little over an hour. That rests on 1,728 TYS to ATL flights, with a median arrival 17 minutes early.
Best time to fly TYS to ATL: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 94.7% of the time and Wednesday flights 93.0%, against 87.8% for the route overall.
Set against the rest of the country, this route's record is 11 points better than the US average of 77.3%. That gap is worth roughly 105 fewer late arrivals for every thousand flights.
Key figures
On time
87.8%
Arrivals under 15 minutes late, of 1,695 completed flights
Avg delay
81 min
Across delayed arrivals only, not all flights
Cancelled
1.79%
National rate is 1.89%
Best carrier
Delta
87.9% on time across 1,727 flights
These figures cover 1,728 flights between September 2025 and August 2026. The median arrival is 17 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 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 | 1,727 | 87.9% | 82 min | 1.80% | 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.
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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.
- 5am–8am346 flights94.7%
- 8am–11am175 flights89.6%
- 11am–2pm278 flights93.8%
- 2pm–5pm454 flights86.8%
- 5pm–8pm442 flights78.8%
- 8pm–5am33 flights90.3%
Scale runs 70% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 94.7% of the time, against 78.8% 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 2pm–5pm window is the busiest, with 454 flights scheduled in it.
Explore
Filter TYS to ATL 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 TYS to ATL, the best departure window is 5am–8am at 94.7% on time and the worst is 5pm–8pm at 78.8%, a wide gap of 15.9 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am94.7%
- 8–11am89.6%
- 11am–2pm93.8%
- 2–5pm86.8%
- 5–8pm78.8%
- 8pm–5am90.3%
best all US flightsScale 60% to 100%.
Across the year
When delays peak on this route
This route's year swings by 16 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 76.7% on time, 16 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 93.0% on time and Sunday the weakest at 80.5%, a spread of 13 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 47% of the 17,000 delay minutes carriers reported here, and the remaining four split what is left.
- 47%Late-arriving aircraft
- 31%Carrier
- 21%National Airspace System
- 1%Extreme weather
47% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 17,000 reported delay minutes here, that single category outweighs weather by 47 to one. The split is drawn from 16,771 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 94.7% on time here.
Cancellations sit at 1.79% against a national 1.89%, which is ordinary. Diversions add another 0.12%.
Connections and stage length
What a delay here actually costs
5.0% 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 a little over an hour, which a normal layover absorbs.
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 82.6% on time across 1,726 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 1,728 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 76.7%, a swing of 16 points. If the dates move at all, move them out of July before you think about anything else. 1,695 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 12.2% of the 1,728 flights in this analysis, against 22.7% 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?
87.8% of flights arrive on time here against a national 77.3%, a difference of 11 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 94.7% on time. The 5pm–8pm window is the weakest at 78.8%, 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 TYS to ATL?
July is the weakest month at 76.7% on time, compared with 92.8% in October. Across the year that is 16 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 route68.8%
- LGA to ATL, a related route75.5%
- TYS to DFW, a related route77.5%
- Delta Air Lines on-time record87.9%
- 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 7.05 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.