Lambert St Louis International (STL) on-time performance, September 2026
5,920 scheduled airline departures from St. Louis in September 2026, 75.2% of them on time. Measured from FAA departure data, updated every morning.
On time, day by day
Share of departures within 15 minutes of schedule, by day. Light bars show each day's departures for context. Worst day: Friday 4 September at 61.9%. Best: Wednesday 9 September at 88.1%.
Airlines at STL, ranked by on-time share
Scheduled airlines with at least 30 departures from STL in the month. Regional partners (SkyWest, Republic, Envoy and the like) appear under their own names; fractional and charter operators are in the totals but not listed.
| Airline | Departures | On time | 45+ min late | Avg delay (min) |
|---|---|---|---|---|
| Federal Express FDX | 42 | 97.6% | 0.0% | -12.4 |
| Mesa Airlines ASH | 40 | 90.0% | 7.5% | 1.9 |
| United Parcel Service UPS | 39 | 89.7% | 7.7% | -4.5 |
| Delta Air Lines DAL | 466 | 89.5% | 5.4% | 2.1 |
| Sun Country Airlines SCX | 121 | 88.4% | 5.0% | -7.6 |
| Alaska Airlines ASA | 106 | 85.8% | 3.8% | 1.2 |
| Jazz (Air Canada Express) JZA | 88 | 85.2% | 8.0% | 6.9 |
| Endeavor Air EDV | 127 | 83.5% | 11.0% | 16.1 |
| American Airlines AAL | 515 | 82.3% | 9.9% | 10.8 |
| SkyWest SKW | 142 | 81.0% | 9.2% | 18.8 |
| Republic Airways RPA | 241 | 79.3% | 12.4% | 15.2 |
| Frontier Airlines FFT | 89 | 78.7% | 7.9% | 9.0 |
| Envoy Air ENY | 106 | 75.5% | 13.2% | 14.2 |
| PSA Airlines JIA | 30 | 73.3% | 16.7% | 23.8 |
| Southwest Airlines SWA | 3,075 | 72.4% | 11.3% | 14.0 |
| United Airlines UAL | 288 | 69.4% | 14.6% | 26.1 |
| GoJet Airlines GJS | 266 | 56.4% | 30.5% | 50.0 |
| KII KII | 40 | 50.0% | 10.0% | 17.0 |
Destinations with the longest delays
Routes from STL with at least 20 departures, by average departure delay.
| To | Flights | On time | Avg delay |
|---|---|---|---|
| IAD Washington | 62 | 59.7% | 41.8 |
| BOS Boston | 140 | 49.3% | 41.0 |
| CVG Cincinnati | 27 | 37.0% | 39.1 |
| ORD Chicago | 418 | 62.9% | 38.7 |
| SFO San Francisco | 53 | 47.2% | 36.5 |
| FRA Frankfurt | 21 | 47.6% | 28.7 |
| MDW Chicago | 146 | 74.7% | 22.4 |
| KECP Panama City Beach | 41 | 73.2% | 20.9 |
| OMA Omaha | 70 | 71.4% | 19.4 |
| EWR Newark | 112 | 79.5% | 18.2 |
Busiest destinations
The ten routes with the most departures from STL this month.
| To | Flights | On time | Avg delay |
|---|---|---|---|
| ORD Chicago | 418 | 62.9% | 38.7 |
| DEN Denver | 324 | 70.7% | 17.2 |
| ATL Atlanta | 287 | 87.5% | 2.1 |
| LGA New York | 287 | 77.4% | 15.1 |
| DFW Dallas-Fort Worth | 215 | 80.5% | 8.0 |
| MSP Minneapolis | 199 | 86.9% | 3.8 |
| DCA Washington | 191 | 75.9% | 9.2 |
| MCO Orlando | 187 | 73.8% | 15.6 |
| LAS Las Vegas | 178 | 72.5% | 14.1 |
| PHX Phoenix | 168 | 73.2% | 14.0 |
Other months for STL
Airline pages for September 2026
How we measure
On time means the aircraft took off within 15 minutes of its scheduled departure, after subtracting the departure airport's normal taxi time at STL (FAA SWIM reports wheels-off, not push-back, so the median taxi time of the last 30 days is taken off every flight first). Average delay is the mean of that taxi-adjusted delay over all departures; early departures count as negative minutes, so an operator that routinely leaves early can show a negative average. 45+ min late is the share of departures that left 45 minutes or more behind schedule, the point at which most connections are at risk.
Scope: scheduled airlines only, the same set as the monthly State of the Sky report (operators with published routes; private, fractional and charter operators are left out), so the two publications give the same numbers for the same month. Departures are counted by scheduled day (UTC). Each day's flights are rolled up overnight and published the next morning; the newest day keeps filling in for a day or two and is only shown once it is substantially complete. Figures can differ by a few tenths of a point from the State of the Sky report for the same month: that report is frozen on the 2nd of the following month, while these pages are rebuilt from the live rollup, which recomputes each airport's taxi baseline nightly and re-rolls the last week of the month as late departure times arrive (September 2026 at SFO: 16,398 departures in both, 69.2% on time here against 69.5% in the report).
Source: FAA System Wide Information Management (SWIM) flight plans and departure times, processed by PlaneTrack. Free to quote with credit to PlaneTrack (CC BY 4.0).