| Clue | Source | Date |
|---|---|---|
| Code for London's largest airport | The Telegraph Cross Atlantic | 06 May 2026 |
| Airport code for London's largest airport | The Telegraph Cross Atlantic | 04 Feb 2026 |
| Heathrow's airport code (3) | The Telegraph Cross Atlantic | 29 Oct 2025 |
| English airport code (1,1,1) | ||
| London's Heathrow Airport code (3) |