Frontier Airlines and Volaris have signed a codeshare agreement, with sales to begin in the coming months.
The two-way codeshare, subject to regulatory approval, will allow the two airlines to add 20 new destinations, says Volaris chief executive Enrique Beltranena.
He estimates that 80 new routes will be launched between the USA and Mexico. Sales of the codeshare flights will begin in the spring, say the two carriers.
Frontier is wholly owned by Indigo Partners, which is an investor in Volaris.
"Many customers travelling between the US and Mexico are forced to pay high fares to fly, and this agreement will provide lower fares to a vast majority of the US and Mexico population," says Frontier chief executive Barry Biffle.
Volaris has a growing US network, currently serving more than 20 destinations including Frontier's Denver hub, FlightGlobal schedules data show. Frontier operates to three Mexican destinations: Cancun, Los Cabos and Puerto Vallarta.
The two airlines currently do not overlap on any routes, FlightGlobal schedules data show.
Both carriers operate Airbus A320 family aircraft, and recently boosted their orderbooks with an order for 430 A320neo family aircraft by Indigo that was firmed up in late 2017. Frontier will receive 100 A320neos and 34 A321neos, while Volaris will take delivery of 46 A320neos and 34 A321neos.