Unlike many airports with Terminals 1 and 2, Sky Harbor has Terminals 3 and 4. Movement between the terminals is through the Phoenix Sky Train with trains arriving and departing every 3 to 5 minutes. It takes approximately 6 minutes to move from one terminal to another. Please note, that there are currently 20 airlines based at Sky Harbor Airport. Some airlines are Delta, Advanced Air, Alaska, Allegiant, Air Canada, Boutique Air, Condor, Contour, Denver Air, Frontier, Hawaiian, JetBlue, JSX, Southwest, Sun Country, and United.