St. Louis Lambert International Airport is the largest and busiest airport in Missouri. The airport is located 22km (20 minutes) northwest of the St. Louis city-centre. It has four runways of 11,019ft (3.4km), 9,003ft (2.7km), 9,001ft, (2.7km), and 7,607ft (2.3km). It has customs clearance and two Fixed Based Operators. St. Louis Lambert International Airport operates 24/7 and does not require slots.