The Brazilian low cost airline Azul has three main hubs which are found in Belo Horizonte, Recife and Viracopos. In total, Azul operates flights to more than 160 destinations, where the majority are domestic or located in the rest of South America. Most low cost carriers aren’t a part of any major alliance, and this goes for Azul as well.
An airline hub is an airport where the airline has a heavy presence and normally some kind of headquarters. On the other hand, a focus city is a destination where the airline operates limited point-to-point routes. In these cities, the airline doesn’t necessarily need to have an office (even though this sometimes is the case). Many low-cost airlines don't use the definition 'hub' but instead define their main airports of operations as an operating base.
IATA Code: AD
ICAO Code: AZU