American Airlines, Inc. (AA or AAL) is a major US-based airline headquartered in Fort Worth, Texas, within the Dallas–Fort Worth metroplex. It is the world's largest airline when measured by fleet size, scheduled passengers carried, and revenue passenger mile. American, together with its regional partners and affiliates, operates an extensive international and domestic network with almost 6,800 flights per day to nearly 350 destinations in more than 50 countries. American Airlines is a founding member of the Oneworld alliance, the third-largest airline alliance in the world. Regional service is operated by independent and subsidiary carriers under the brand name American Eagle.