Allegiant Air will begin two new routes connecting existing destinations in its network.
The Las Vegas-based carrier will begin flights between Las Vegas and Louisville from 16 November, and between Austin and Columbus Rickenbacker from 16 February 2018.
Allegiant will fly twice weekly on each route.
It will compete against Southwest Airlines on Las Vegas-Louisville, FlightGlobal schedules data show.
Allegiant will be the only airline operating nonstop between Austin and Columbus Rickenbacker. However, rival Frontier Airlines had earlier announced plans to begin service between Austin and Columbus International, which is a 30min drive from Rickenbacker.