American Airlines
American currently seems to be the most popular airline flying into St Thomas (STT).
Direct flights from Miami (MIA) & New York (JFK). Direct flights from nearly everywhere else into their Caribbean hub in San Juan, Puerto Rico (SJU), connecting on to STT with hourly American Eagle flights (approx. 35 min. flight).

Delta Air Lines
Two flights a day directly to St. Thomas (STT) from Atlanta (ATL).

Continental Airlines
Flights from Newark (EWR) several times a week, but provides expanded service to San Juan, Puerto Rico (SJU). See list of commuter airlines below.

US Airways
One direct flight a day from Philadelphia (PHL) and Charlotte (CLT).

United Airlines
Daily flights from Chicago (ORD), Charlotte (CLT), and Washington, D.C.'s Dulles (IAD).

Alternative commuter airlines that connect St Thomas (STT) and San Juan, PR (SJU):

Cape Air
Seaborne Airlines
Air Sunshine