Claim: In 2019, the busiest domestic route at Adolfo Suárez Madrid–Barajas Airport is the Galicia_(Spain)Santiago de Compostela, which is served with five carriers, while the least busy route is Galicia_(Spain)Vigo, and is only served with one carrier.
Evidence: Busiest domestic routes at Adolfo Suárez, Madrid–Barajas International Airport (2019) Galicia_(Spain)Santiago de Compostela 7 Air Europa, Iberia Express, Ryanair