Stockholm Västerås Airport (IATA: VST, ICAO: ESOW), also known as Hässlö Flygplats, is a minor international airport located near the city of Västerås, Sweden. The airport is located 110 km (70 mi) west of Stockholm, and is outside of Stockholm County, but is included in STO, the IATA airport code for Stockholm airports. The airport handled a total of 78,652 passengers in 2024, making it Sweden's 18th-busiest airport. On the airport grounds, the Västerås Flygmuseum offers visitors a glimpse into Sweden’s rich aviation heritage, featuring a collection of historic military and civilian aircraft, helicopters, engines, and aviation-related artifacts. The museum provides an immersive experience for aviation enthusiasts, showcasing both static displays and themed exhibitions that highlight the evolution of Swedish aviation and aerospace technology. In addition, the airport is home to a local flight school, supporting pilot training and general aviation activities year-round.