Cassidy International Airport — Kiritimati, Kiribati

Cassidy International Airport, bearing the code CXI, occupies Kiritimati, an atoll better known in English as Christmas Island, part of Kiribati's remote Line Islands group in the central Pacific. Its unusually long runway traces back to the mid-twentieth century, when British and American forces used the atoll as a staging ground for nuclear weapons tests, leaving behind aviation infrastructure far larger than the local population would otherwise require. Today CXI connects the island to Fiji and, at various points, to Honolulu, supporting a small but growing tourism trade built around bonefishing and birdlife rather than the strategic military purposes of decades past. Kiritimati holds the distinction of being among the largest coral atolls on the planet by land area, and its position near the International Date Line means Kiribati as a nation adjusted its calendar boundaries so the whole country could share the same date, a quirk of geography that leaves CXI among the first airports anywhere to greet each new day.