As for abandoned air fields in Vietnam and neighboring countries, I grew up in the subtropics and, in fact, my high school was built on what had been a Naval Air Field during WWII.
Unless a landing strip is maintained very carefully, vegetation takes over quickly in that sort of climate. I doubt those "thousands of abandoned airfields" in Indochina are still capable of handling a 777 landing.
Unless a landing strip is maintained very carefully, vegetation takes over quickly in that sort of climate. I doubt those "thousands of abandoned airfields" in Indochina are still capable of handling a 777 landing.