Carrier performance at one airport
UA→ATL
United Airlines at Hartsfield-Jackson Atlanta International
- Departures
- 7,672
- Period
- September 2025 to August 2026
- Routes
- 6
- Rank here
- #1 of 12
United Airlines at Atlanta lands a B, 2 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 7,672 flights, of which United Airlines flew 7,672 at 79.7% on time.
Measured against the airport rather than the country, United Airlines runs 2 points ahead of the 77.8% weighted average across all carriers at ATL. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
79.7%
7,528 completed departures
Avg delay
84 min
Across delayed flights only
Cancelled
1.51%
At ATL, this carrier only
Rank here
#1
Of 12 carriers clearing the floor at ATL
These figures cover 7,672 flights between September 2025 and August 2026. Beyond the headline rate, 8.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Against the competition
Every carrier at ATL, ranked
The choice of carrier is not cosmetic here. United Airlines arrives on time 79.7% of the time; Frontier Airlines manages 63.7%. Sample sizes sit next to every figure, because a two-point gap across 20,778 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 7,672 | 79.7% | 84 min | 1.51% | B |
| Delta Air Lines | 240,917 | 79.5% | 59 min | 1.67% | B |
| Alaska Airlines | 1,359 | 78.7% | 54 min | 0.81% | B+ |
| PSA Airlines | 3,319 | 77.6% | 110 min | 5.33% | B− |
| Southwest Airlines | 17,133 | 76.4% | 59 min | 1.10% | B |
| American Airlines | 6,907 | 75.7% | 106 min | 1.90% | B |
| SkyWest Airlines | 6,699 | 75.1% | 106 min | 2.58% | B |
| Republic Airways | 3,135 | 74.9% | 84 min | 4.85% | C− |
| Envoy Air | 1,064 | 72.1% | 69 min | 2.54% | C |
| Spirit Airlines | 3,886 | 70.7% | 77 min | 4.01% | C− |
| JetBlue Airways | 2,858 | 69.1% | 89 min | 4.55% | C− |
| Frontier Airlines | 20,778 | 63.7% | 83 min | 2.42% | D |
PSA Airlines cancels 5.3% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Where United Airlines flies from ATL
United Airlines operates 6 routes out of ATL with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| ATL to EWR · Newark | 2,024 | 79.0% | 90 min | 2.92% | B |
| ATL to ORD · Chicago | 1,717 | 72.7% | 92 min | 1.81% | C |
| ATL to IAH · Houston | 1,281 | 85.3% | 74 min | 0.70% | A+ |
| ATL to IAD · Washington | 1,091 | 81.6% | 78 min | 0.92% | B+ |
| ATL to DEN · Denver | 923 | 85.9% | 84 min | 0.43% | A+ |
| ATL to SFO · San Francisco | 636 | 76.9% | 69 min | 0.47% | B+ |
Flight by flight
United Airlines flight numbers from ATL
9 United Airlines flight numbers leaving ATL flew their main route often enough to have a record of their own. Grouped by destination.
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against 16 points between the best and worst carrier.
- 5am–8am1,414 flights89.8%
- 8am–11am1,452 flights85.7%
- 11am–2pm1,487 flights83.9%
- 2pm–5pm1,683 flights74.5%
- 5pm–8pm1,410 flights68.0%
- 8pm–5am226 flights60.7%
Scale runs 50% to 95%.
The 8pm–5am window is where this operation falls apart: 60.7% on time, against 89.8% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 2pm–5pm window is the busiest, with 1,683 flights scheduled in it.
Across the year
Seasonal pattern
July is the worst month at 72.5% on time, 15 points below February, the best at 87.8%. 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. July was the busiest month here, with 716 flights.
Delay causes
What holds this operation up
- 43%National Airspace System
- 31%Late-arriving aircraft
- 22%Carrier
- 3%Extreme weather
43% 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 56,000 minutes out of 129,000, against a national NAS share of 21%. The split is drawn from 128,820 reported delay minutes.
Cancellations sit at 1.51% against a national 1.89%, which is ordinary. Diversions add another 0.36%.
8.9% 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 sample behind these figures is 7,672 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.
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 87.8% on time and July 72.5%, a swing of 15 points. If the dates move at all, move them out of July before you think about anything else. 7,528 completed flights over 12 months sit behind that.
Common questions
United Airlines at ATL
How often is United Airlines at ATL 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 20.3% of the 7,672 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 United Airlines at ATL?
United Airlines leads at 79.7% on time across 7,672 flights. Frontier Airlines is at the other end on 63.7%, a gap of 16 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 United Airlines at ATL?
The 5am–8am departure window is the strongest at 89.8% on time. The 8pm–5am window is the weakest at 60.7%, 29 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 United Airlines at ATL?
July is the weakest month at 72.5% on time, compared with 87.8% in February. Across the year that is 15 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
- United Airlines network-wide record
- Hartsfield-Jackson Atlanta International (ATL) all carriers
- ATL to EWR route record79.0%
- ATL to ORD route record72.7%
- ATL to IAH route record85.3%
- ATL to IAD route record81.6%
- Do airlines run better at their own hubs?
- The best time of day to fly, according to 7.05 million flight records
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.