Question: Which air base was at the western end of an American twin-engine, medium bomber's air route.
Sentence (from "Osan Air Base"): Osan Air Base is also the departure and arrival point for U.S. government-contracted "Patriot Express" flights bringing service members and their family members to South Korea from Seattle-Tacoma International Airport in the U.S. state of Washington, Misawa Air Base and Yokota Air Base in Japan.
Relevant evidence: No