U.S. air carriers announce sales

DENVER, July 7 (UPI) -- Three low-cost airlines announced a sale Tuesday on fares on many routes, including fares below $100 on shorter routes.

Southwest, AirTran and Frontier are all offering reduced-price flights, USA Today reported. At least one major carrier, American Airlines, also was starting to follow suit, Denver Business Journal reported.

Southwest and Frontier are two of the three busiest carriers serving Denver. Denver Business Journal reported Frontier is offering discounts on some flights between Aug. 10 and Jan. 15 with prices as low as $34 if flights are booked online by July 14. Southwest announced one-way tickets for between $30 and $90.

AirTran announced prices as low as $39 each way for off-peak days on some short routes, USA Today reported.

Southwest is the nations largest low-cost air carrier, tied its reduced fares to the length of flights.

AirTran's sale is good for flights through Nov. 11 if customers book by Thursday. Lowest fares are for Tuesday, Wednesday and Saturday travel.