Denver, Colorado - Frontier Airlines has reached an agreement with Mexican airline Volaris to offer a first-of-its-kind code-share partnership in which customers can book flights on one airline through the other - a move that is expected to reduce the headaches of a number of customers flying between the United States and Mexico.

Code-share agreements are common between larger airlines, especially those in international alliances, but the partnership between two ultra-low-cost carriers makes this deal unique. Leaders from Denver-headquartered Frontier and Mexico City-based Volaris said the agreement will help people achieve lower-cost connections between the neighboring countries - and that it could increase the number of passengers of one airline that choose to use the other carrier as well.

"Many customers traveling between the U.S. and Mexico are forced to pay high fares to fly, and this agreement will provide lower fares to a vast majority of the U.S. and Mexico population," said Barry Biffle, Frontier president and CEO, on Tuesday. "As the leading ultra-low-cost carrier in Mexico, Volaris is an ideal partner with which to align and we look forward to work together to deliver low fares to millions of people."

Frontier currently flies nonstop to three leisure-focused Mexican locations from Denver - Cancun on year-round flights, and Puerto Vallarta and Cabo San Lucas on seasonal routes. Volaris flies from Denver International Airport to four Mexican cities - Chihuahua, Guadalajara, Mexico City and Monterey.

The agreement remains subject to federal government approval. If that goes through, officials estimated the code-share tickets should be available by this spring.