Customers can now buy flights with Aer Lingus or American Airlines between Dublin-Philadelphia and Dublin-Chicago.
The new agreement enables Aer Lingus customers to book direct flights from Dublin to Charlotte, North Carolina, and Dallas-Fort Worth Texas with American Airlines via aerlingus.com.
Aer Lingus customers can also book codeshare connecting travel with American Airlines to destinations such as Albuquerque, Nashville, Las Vegas, Kansas City, Portland, San Jose, Tampa and Tucson.
The initial codeshare agreement between both airlines launched last year.
American Airlines, meanwhile, is operating a record international programme this winter until 30 March, offering 13% more seats than last year.
The programme includes more than 400 flights to 117 destinations.
American Airlines will offer 14% more seats to Dublin, with an expanded year-round service from Dallas-Fort Worth Texas, and an earlier seasonal restart of flights to Charlotte alongside the existing service to Philadelphia.
