YX4521
YX4521 (Republic Airways) is a multi-stop service on 15 routes, busiest Hartford to Chicago. Of 736 departures recorded from October 2024 to July 2026, 83.5% left on time, according to the US BTS.
- On-time departures83.5%of 736 flights
- Average delay8.4 min
- July 202627▲ 3.8%vs July 2025
- Cancelled5.3%
- Legs flown under this number15
according to the US BTS · Oct 12, 2024 → Jul 31, 2026 domestic flights only
Recorded departures by month
Partial coverage: domestic flights only · 22 of 22 periods have data
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 | 48 | 56 | ▲ 16.7% |
| February | 48 | 23 | ▼ 52.1% |
| March | 28 | 48 | ▲ 71.4% |
| April | 54 | 44 | ▼ 18.5% |
| May | 62 | 43 | ▼ 30.6% |
| June | 30 | 26 | ▼ 13.3% |
| July | 26 | 27 | ▲ 3.8% |
| August | 26 | – | – |
| September | 27 | – | – |
| October | 5 | – | in progress |
| November | 3 | – | – |
| December | 38 | – | – |
| Year to date (Jan–Jul) | 296 | 267 | ▼ 9.8% |
according to the US BTS · October 2024 → July 2026
On-time departures by month
Partial coverage: domestic flights only · 22 of 22 periods have data
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% | 88.2% | ▼ 7.8% |
| February | 81.3% | 65.2% | ▼ 19.7% |
| March | 92.3% | 72.1% | ▼ 21.9% |
| April | 85.2% | 76.2% | ▼ 10.6% |
| May | 95.2% | 88.1% | ▼ 7.4% |
| June | 64.0% | 75.0% | ▲ 17.2% |
| July | 86.7% | 69.6% | ▼ 19.7% |
| August | 80.8% | – | – |
| September | 92.6% | – | – |
| October | 80.0% | – | in progress |
| November | 100.0% | – | – |
| December | 68.4% | – | – |
| Year-to-date average (Jan–Jul) | 85.8% | 76.3% | ▼ 11.0% |
according to the US BTS · October 2024 → July 2026
Average departure delay by month
Partial coverage: domestic flights only · 22 of 22 periods have data
according to the US BTS · October 2024 → July 2026
Cancelled departures by month
Partial coverage: domestic flights only · 22 of 22 periods have data
The most recent periods19 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | 1 | 5 | ▲ 400.0% |
| February | 0 | 0 | – |
| March | 2 | 5 | ▲ 150.0% |
| April | 0 | 2 | – |
| May | 0 | 1 | – |
| June | 5 | 2 | ▼ 60.0% |
| July | 11 | 4 | ▼ 63.6% |
| August | 0 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 1 | – | – |
| December | 0 | – | – |
| Year to date (Jan–Jul) | 19 | 19 | 0.0% |
according to the US BTS · October 2024 → July 2026
This is not a forecast
This is a historical record of departures already flown, not a forecast for your flight.
This number flies several legs
Several legs: the headline figure averages all of them. See the leg table.
Cancellation share
- Not cancelled 94.7% 697
- Cancelled 5.3% 39
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
88 of 8
| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| BDL ORD Bradley International Airport – Chicago O'Hare International Airport | 1,257 | 7.8 min | 81.6% | 150 |
| ORD BDL Chicago O'Hare International Airport – Bradley International Airport | 1,257 | 10.6 min | 81.0% | 148 |
| LGA BUF LaGuardia Airport – Buffalo Niagara International Airport | 469 | 16.9 min | 73.3% | 138 |
| ORD CMH Chicago O'Hare International Airport – John Glenn Columbus International Airport | 475 | -1.9 min | 95.2% | 62 |
| CMH ORD John Glenn Columbus International Airport – Chicago O'Hare International Airport | 475 | 4.2 min | 87.1% | 62 |
| STL LGA St. Louis Lambert International Airport – LaGuardia Airport | 1,426 | 8.3 min | 84.4% | 33 |
| LGA STL LaGuardia Airport – St. Louis Lambert International Airport | 1,426 | 4.3 min | 90.9% | 33 |
| PIT ORD Pittsburgh International Airport – Chicago O'Hare International Airport | 662 | 6.1 min | 90.0% | 30 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 20 | 20 | 100.0% | 0 |
| November 2024 | 29 | 29 | 93.1% | 0 |
| December 2024 | 25 | 25 | 84.0% | 0 |
| January 2025 | 48 | 47 | 95.7% | 1 |
| February 2025 | 48 | 48 | 81.3% | 0 |
| March 2025 | 28 | 26 | 92.3% | 2 |
| April 2025 | 54 | 54 | 85.2% | 0 |
| May 2025 | 62 | 62 | 95.2% | 0 |
| June 2025 | 30 | 25 | 64.0% | 5 |
| July 2025 | 26 | 15 | 86.7% | 11 |
| August 2025 | 26 | 26 | 80.8% | 0 |
| September 2025 | 27 | 27 | 92.6% | 0 |
| October 2025 | 5 | 5 | 80.0% | 0 |
| November 2025 | 3 | 2 | 100.0% | 1 |
| December 2025 | 38 | 38 | 68.4% | 0 |
| January 2026 | 56 | 51 | 88.2% | 5 |
| February 2026 | 23 | 23 | 65.2% | 0 |
| March 2026 | 48 | 43 | 72.1% | 5 |
| April 2026 | 44 | 42 | 76.2% | 2 |
| May 2026 | 43 | 42 | 88.1% | 1 |
| June 2026 | 26 | 24 | 75.0% | 2 |
| July 2026 | 27 | 23 | 69.6% | 4 |