YX4537
YX4537 (Republic Airways) is a multi-stop service on 26 routes, busiest St Louis to Chicago. Of 539 departures recorded from October 2024 to July 2026, 85.7% left on time, according to the US BTS.
- On-time departures85.7%of 539 flights
- Average delay5.5 min
- July 202662▲ 106.7%vs July 2025
- Cancelled3.9%
- Legs flown under this number26
Recorded departures by month
All legs under this number combined; see the leg table.
The most recent periods19 periods
| Period | Departures 2025 | Departures 2026 | Change vs last year |
|---|---|---|---|
| January | 25 | 2 | ▼ 92.0% |
| February | 28 | 15 | ▼ 46.4% |
| March | 7 | 30 | ▲ 328.6% |
| April | 29 | 27 | ▼ 6.9% |
| May | 27 | 39 | ▲ 44.4% |
| June | 29 | 60 | ▲ 106.9% |
| July | 30 | 62 | ▲ 106.7% |
| August | 23 | – | – |
| September | 24 | – | – |
| October | 4 | – | in progress |
| November | 3 | – | – |
| December | 23 | – | – |
| Year to date (Jan–Jul) | 175 | 235 | ▲ 34.3% |
according to the US BTS · October 2024 → July 2026
On-time departures by month
On time = departure within 15 minutes of schedule. Non-cancelled flights with a recorded delay only.
The most recent periods19 periods
| Period | On time 2025 | On time 2026 | Change vs last year |
|---|---|---|---|
| January | 95.7% | 100.0% | ▲ 4.5% |
| February | 85.2% | 76.9% | ▼ 9.7% |
| March | 83.3% | 75.9% | ▼ 9.0% |
| April | 85.7% | 81.5% | ▼ 4.9% |
| May | 100.0% | 89.7% | ▼ 10.3% |
| June | 86.2% | 70.2% | ▼ 18.6% |
| July | 90.0% | 73.2% | ▼ 18.7% |
| August | 95.5% | – | – |
| September | 95.8% | – | – |
| October | 100.0% | – | in progress |
| November | 100.0% | – | – |
| December | 90.9% | – | – |
| Year-to-date average (Jan–Jul) | 89.4% | 81.1% | ▼ 9.4% |
according to the US BTS · October 2024 → July 2026
Average departure delay by month
according to the US BTS · October 2024 → July 2026
Cancelled departures by month
The most recent periods19 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | 2 | 0 | ▼ 100.0% |
| February | 1 | 2 | ▲ 100.0% |
| March | 1 | 1 | 0.0% |
| April | 1 | 0 | ▼ 100.0% |
| May | 1 | 0 | ▼ 100.0% |
| June | 0 | 3 | – |
| July | 0 | 6 | – |
| August | 1 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 1 | – | – |
| December | 1 | – | – |
| Year to date (Jan–Jul) | 6 | 12 | ▲ 100.0% |
according to the US BTS · October 2024 → July 2026
This is a historical record of departures already flown, not a forecast for your flight.
Several legs: the headline figure averages all of them. See the leg table.
Cancellation share
- Not cancelled 96.1% 518
- Cancelled 3.9% 21
Share of all recorded flights in the period, all legs. · Oct 12, 2024 → Jul 31, 2026
On time, leg by leg
Departures within 15 minutes of schedule; small figure = departures recorded.
Legs flown under this number
7| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| STL ORD St. Louis Lambert International Airport – Chicago O'Hare International Airport | 415 | 14.4 min | 72.7% | 72 |
| ORD STL Chicago O'Hare International Airport – St. Louis Lambert International Airport | 415 | 12.9 min | 76.8% | 72 |
| DCA TYS Ronald Reagan Washington National Airport – McGhee Tyson Airport | 702 | 6.9 min | 88.2% | 52 |
| LGA PIT LaGuardia Airport – Pittsburgh International Airport | 538 | 0.3 min | 86.8% | 38 |
| IAH ORD George Bush Intercontinental Airport – Chicago O'Hare International Airport | 1,491 | -2.2 min | 94.1% | 36 |
| ORD IND Chicago O'Hare International Airport – Indianapolis International Airport | 286 | 1.7 min | 90.3% | 31 |
| DCA LGA Ronald Reagan Washington National Airport – LaGuardia Airport | 345 | 20.4 min | 72.4% | 30 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 40 | 40 | 95.0% | 0 |
| November 2024 | 8 | 8 | 100.0% | 0 |
| December 2024 | 4 | 4 | 100.0% | 0 |
| January 2025 | 25 | 23 | 95.7% | 2 |
| February 2025 | 28 | 27 | 85.2% | 1 |
| March 2025 | 7 | 6 | 83.3% | 1 |
| April 2025 | 29 | 28 | 85.7% | 1 |
| May 2025 | 27 | 26 | 100.0% | 1 |
| June 2025 | 29 | 29 | 86.2% | 0 |
| July 2025 | 30 | 30 | 90.0% | 0 |
| August 2025 | 23 | 22 | 95.5% | 1 |
| September 2025 | 24 | 24 | 95.8% | 0 |
| October 2025 | 4 | 4 | 100.0% | 0 |
| November 2025 | 3 | 2 | 100.0% | 1 |
| December 2025 | 23 | 22 | 90.9% | 1 |
| January 2026 | 2 | 2 | 100.0% | 0 |
| February 2026 | 15 | 13 | 76.9% | 2 |
| March 2026 | 30 | 29 | 75.9% | 1 |
| April 2026 | 27 | 27 | 81.5% | 0 |
| May 2026 | 39 | 39 | 89.7% | 0 |
| June 2026 | 60 | 57 | 70.2% | 3 |
| July 2026 | 62 | 56 | 73.2% | 6 |