Hi, Rubin.

PVD is my home airport. US is the largest carrier, but all of the major airlines fly out of here.

Off the top of my head:

USAir - PIT,PHL,BWI,DCA,CLT,ALB,LGA
Continental - EWR,CLE,IAH
UAL - Chicago (O'Hare)
Delta - ATL,CVG
Northwest - DTW

I believe Delta Express and Metrojet have direct flights to Florida. Express flights also to all NYC airports.

For European flights, Boston has many direct routes. Traffic is terrible with the Big Dig, but I usually take the Bonanza bus from Providence (free parking, express lanes).

I hope this helps.