Delta Air Lines and Aeromexico are to establish a trans-border alliance between the US and Mexico.

The airlines were granted antitrust immunity by the US Department of Transportation to allow them to establish a joint co-operation agreement.

The regulatory approval represents an “important milestone” in Delta’s ambition to acquire 49% of the Mexican carrier to further strengthen the partnership.

The two airlines plan to collaborate to expand destinations and frequencies, improve connecting schedules and provide seamless operations.

Delta will offer a strong presence through its hubs in Atlanta, Detroit, Los Angeles, Minneapolis-St. Paul, New York, Salt Lake City and Seattle, while Aeromexico will offer improved access to Mexico through its hubs in Mexico City, Monterrey and Guadalajara.

The agreement will allow the carriers to improve the experience on the ground, allowing the them to co-locate and invest in airport facilities by improving gates and lounges. They will also increase joint sales and marketing initiatives.

Delta chief executive Ed Bastian said: “Together, Delta and Aeromexico are stronger in the US-Mexico market than either airline can be on its own.

“The partnership will make it possible for us to offer customers more flights to more destinations, with more choices every time someone travels across the border. We will offer industry-leading reliability, great service and an unmatched array of options.”

He added: “Our partnership means growth of services and jobs for both Delta and Aeromexico.”

Aeromexico chief executive Andrés Conesa said: “This agreement will mark the beginning of a new era in the aviation of North America, as the first and the largest cross-border alliance between Mexico and the United States.

“It is the next step in our relationship, and our networks will provide more benefits to our customers while increasing the options for connectivity, products and services.”