How was Khe Sanh resupplied, unlike Dien Bien Phu?

Like Dien Bien Phu, Khe Sanh was isolated: both lay in valleys surrounded by high, mountainous terrain. With the enemy controlling the surrounding countryside, Khe Sanh was cut off from all supply other than by air, just as had happened to Dien Bien Phu. That total isolation, with the air as the only resupply route, lasted 77 days.

Although Khe Sanh was isolated, the distance to the nearest allied bases was measured in tens of miles rather than hundreds, and the flight time between the combat base and the nearest supply base was minutes, not hours. In 1954, the French air transport squadrons were equipped with twin-engine C-47s, sturdy and reliable but also very slow and limited in payload for the 400-mile round trip required to supply the isolated base at Dien Bien Phu. In 1968, Westmoreland had at his disposal a massive airlift asset, with three full wings of fast, modern turboprop C-130 Hercules, capable of carrying loads of 35,000 pounds.

Westmoreland had enough airlift resources to keep the Marine base supplied during a prolonged siege, unlike the French with their slower C-47 transports. During one stretch of the siege, Air Force deliveries to Khe Sanh averaged 50 tons, with 18 C-130 landings a day. A major problem for the French at Dien Bien Phu had been their inability to suppress enemy ground fire.