The best price found from United States to Austria is on December 13th, 2015, travelling with Condor. See more options, compare prices and book: search flights.
Vienna is the main transport hub for Austria, but Graz, Linz, Klagenfurt, Salzburg and Innsbruck all receive international flights. Flights to these cities are often a cheaper option than those to the capital, as are flights to Airport Letisko (Bratislava Airport), which is only 60km east of Vienna, in Slovakia. Bregenz has no airport; your best bet is to fly into Friedrichshafen in Germany or Altenrhein in Switzerland.
Among the low-cost airlines, Air Berlin and Niki fly to Graz, Air Berlin, Transavia, easyJet and Niki to Innsbruck, germanwings and Ryanair to Klagenfurt, Ryanair to Linz, Air Berlin and Ryanair to Salzburg, and Ryanair to Bratislava (for Vienna). Air Berlin, easyJet and germanwings fly to Vienna Airport.