UA21
1,216 recorded sectors across 4 years, operated by United Airlines.
Flown as AMS–IAH, AMS–IAD, IAH–AMS. More than one sector means either a multi-stop service or a route that changed over the years.
Years held
| Year | Sectors | Range |
|---|---|---|
| 2026 | 212 | 1 Jan – 31 Jul |
| 2025 | 367 | 1 Jan – 31 Dec |
| 2024 | 366 | 1 Jan – 31 Dec |
| 2023 | 271 | 3 Apr – 31 Dec |