Las Vegas-based Allegiant Air will launch service between Cincinnati and Fort Lauderdale from 9 October, followed by service between Cincinnati and Phoenix Mesa from 12 November.
The carrier will operate four times weekly to Fort Lauderdale and twice weekly to Phoenix.
Separately, Allegiant will also add frequencies on its flights to Orlando Sanford, St Petersburg-Clearwater and Punta Gorda from Cincinnati.
Allegiant's new flights will grow the airline's presence at Cincinnati to 18 flights weekly from seven.
"Since we began operating in Cincinnati earlier this year, the community has shown an overwhelming appetite for access to affordable vacation travel. We are confident the community will appreciate the convenience of flying non-stop to these new destinations and the value of bundling their air, hotel and car rental reservation together," says Allegiant's president Andrew Levy.
Allegiant will compete against Delta Air Lines on Cincinnati-Fort Lauderdale, and will be the only carrier to operate non-stop between Cincinnati and Phoenix, schedules in Innovata show.