Route Reliability

Route reliability

St. Louis (STL) to Atlanta (ATL): which airline is most on time?

On-time arrivals, cancellations and long delays for every airline that reported nonstop flights from St. Louis, MO (STL) to Atlanta, GA (ATL), September 2025 to August 2026.

Historical performance Official DOT data through August 2026 · Not live flight status

St. Louis, MOAtlanta, GA

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Three-letter airport codes, nonstop U.S. domestic flights. One direction at a time.

Route at a glance · September 2025 to August 2026

STL to ATL

St. Louis, MO to Atlanta, GA

On time
82.9%vs 75.6% U.S. average Better than average
Cancelled
1.6%vs 1.9% U.S. average About average
60+ min late
5.3%vs 8.1% U.S. average Better than average
Scheduled flights
3,673in 12 months3 airlines
Most reliable airline
Delta Air Lines87.6% on time · 2,348 flights

On time more often than the U.S. average, with a typical cancellation rate.

Compared with all U.S. flights, September 2025 to August 2026. “About average” means within 1.5 points for on time, 0.3 for cancelled and 1 for 60+ minutes late.

Airlines on this route

Ranked by on-time arrival

Airlines from STL to ATL, September 2025 to August 2026. Rates are shares of all scheduled flights.
Airline On time Cancelled 60+ min late Avg delay when late Diverted Flights
1. Delta Air Lines Most reliable 87.6% 1.9% 3.8% 77 min 0.3% 2,348
2. Southwest Airlines 78.0% 1.1% 6.0% 53 min 0.4% 1,091
3. Frontier Airlines Small sample (under 300 flights) 59.4% 1.7% 17.1% 96 min 0.4% 234

On time = arrived within 15 minutes of schedule. Avg delay when late = average arrival delay of flights 15+ minutes late. "Most reliable" needs at least 300 flights in 12 months. Tap a heading to sort.

What this means

Delta Air Lines has the strongest record on this route.

  • Delta Air Lines had the best on-time record from St. Louis (STL) to Atlanta (ATL): 87.6% of its 2,348 scheduled flights arrived within 15 minutes of schedule, compared with 78.0% for Southwest Airlines.
  • 1.6% of flights on this route were cancelled (about 1 in 63), about the same as the U.S. average of 1.9%.
  • 5.3% of flights, about 1 in 19, arrived an hour or more late. When a flight was late (15+ minutes), the average arrival delay was 71 min.
  • Overall, 82.9% of flights on this route arrived on time, 7.3 points higher than the U.S. average of 75.6%.
  • Over the last 3 years, September was the most reliable month on this route (91.6% on time) and July the least reliable (73.5%).
  • Cancellations peaked in January, when 4.8% of flights were cancelled.
  • Flights scheduled to depart 8 am to 9 am were the most punctual (95.4% on time); flights scheduled to depart 7 pm to 8 pm were the least (64.7%).
  • In the other direction, Atlanta (ATL) to St. Louis (STL), 80.5% of flights were on time and 1.4% were cancelled. Compare airlines ATL to STL.

Best and worst months to fly STL to ATL

Jan 80.9%
Feb 86.9%
Mar 82.7%
Apr 85.8%
May 79.7%
Jun 82.0%
Jul 73.5%
Aug 86.0%
Sep 91.6%
Oct 91.5%
Nov 88.5%
Dec 82.4%
Share of scheduled flights on time 12-month average 82.9%
All airlines combined, by calendar month, September 2023 to August 2026 (3 years pooled). Scale starts at zero.
Show as table
PeriodOn timeFlights
January 80.9% 807
February 86.9% 749
March 82.7% 855
April 85.8% 879
May 79.7% 945
June 82.0% 943
July 73.5% 979
August 86.0% 950
September 91.6% 896
October 91.5% 940
November 88.5% 876
December 82.4% 924
Best and worst calendar month by airline, September 2023 to August 2026.
AirlineBest monthWorst month
Delta Air Lines October (94.4%) July (78.8%)
Southwest Airlines September (88.7%) July (65.0%)

Month by month, last 12 months

Sep 95.0%
Oct 89.7%
Nov 81.0%
Dec 79.1%
Jan 82.1%
Feb 88.2%
Mar 76.0%
Apr 84.3%
May 80.3%
Jun 80.8%
Jul 75.5%
Aug 83.1%
Share of scheduled flights on time U.S. average 75.6%
All airlines combined, September 2025 to August 2026. Scale starts at zero.
Show as table
PeriodOn timeFlights
Sep 2025 95.0% 317
Oct 2025 89.7% 348
Nov 2025 81.0% 284
Dec 2025 79.1% 311
Jan 2026 82.1% 279
Feb 2026 88.2% 254
Mar 2026 76.0% 283
Apr 2026 84.3% 299
May 2026 80.3% 330
Jun 2026 80.8% 318
Jul 2026 75.5% 330
Aug 2026 83.1% 320

Best and worst departure times

<6a Insufficient sample
6a 92.0%
7a 92.4%
8a 95.4%
9a 91.9%
10a 90.1%
11a 85.5%
12p 83.2%
1p 82.5%
2p 83.3%
3p 80.3%
4p 67.2%
5p 77.8%
6p 71.3%
7p 64.7%
8p 68.1%
9p Insufficient sample
Share of scheduled flights on time
By scheduled local departure hour at STL, September 2025 to August 2026. Hours with no scheduled flights are omitted. Scale starts at zero.
Show as table
PeriodOn timeFlights
Departing before 6 am Insufficient sample 3
Departing 6 am to 7 am 92.0% 363
Departing 7 am to 8 am 92.4% 436
Departing 8 am to 9 am 95.4% 108
Departing 9 am to 10 am 91.9% 270
Departing 10 am to 11 am 90.1% 374
Departing 11 am to noon 85.5% 214
Departing noon to 1 pm 83.2% 113
Departing 1 pm to 2 pm 82.5% 275
Departing 2 pm to 3 pm 83.3% 60
Departing 3 pm to 4 pm 80.3% 299
Departing 4 pm to 5 pm 67.2% 241
Departing 5 pm to 6 pm 77.8% 338
Departing 6 pm to 7 pm 71.3% 314
Departing 7 pm to 8 pm 64.7% 167
Departing 8 pm to 9 pm 68.1% 94
Departing 9 pm to 10 pm Insufficient sample 4
Woman at an airport window watching a plane take off
Photo: Depositphotos (licensed stock, illustrative only). Credits

Sources & data dates

Source
U.S. DOT Bureau of Transportation Statistics, Reporting Carrier On-Time Performance (1987-present)
Period
September 2025 to August 2026 (12 months); month-of-year patterns September 2023 to August 2026
Data through
August 2026
Processed
2026-11-03
Scope
Nonstop scheduled flights from St. Louis, MO (STL) to Atlanta, GA (ATL), one direction. Airlines that report to the DOT only.
Method
Rates use all scheduled flights as the denominator; cancelled and diverted flights count as not on time. Figures based on fewer than 50 scheduled flights are suppressed. Full methodology.

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