Updated

The CEO of discount carrier Spirit Airlines says he isn't worried about competing against new, cheaper fares from American and United.

The "basic economy" fares being offered by American and United are designed to attract the kind of thrifty fliers that have helped Spirit double in revenue in four years.

Spirit CEO Robert Fornaro says his customers know what they're getting for a "bare fare."

He said Wednesday that American and United are trying to lure customers with a cheap fare, then convince them to buy a pricier ticket with more amenities.