Southwest Airlines & AA sold most tickets

As has become common, Southwest Airlines carried more total system and more domestic passengers for the first seven months than any other US airline, while American Airlines carried more international passengers than any other US carrier.
Among US airlines, Southwest sold 61.6 million airline tickets = passengers on its system in the first seven months of 2008, the most of any airline. In July, Southwest carried 9.4 million passengers on its system, the most of any airline.
Among airports, Atlanta Hartsfield-Jackson was the busiest US airport in the first seven months of 2008, with 25.3 million domestic and international passenger boardings. In July, Atlanta Hartsfield-Jackson was the busiest US airport with 4.1 million domestic and international passenger boardings on US carriers.