This airport is less than 40 minutes from downtown Leavenworth! This is the best option for guests who are not interested in renting a rental car :)
Yakima Airport is 1 hour 45 minutes from the town of Leavenworth. Flights to Yakima are typically more expensive than Seattle, but the airport is slightly closer.
SeaTac is 2 hour 20 minutes from Leavenworth. Seattle is a major airport, usually offering inexpensive, nonstop flights from Nashville, St Louis, Atlanta, Chicago, and New York.