Maryland officials say Baltimore-Washington International Thurgood Marshall Airport hit an all-time record for passenger traffic in 2010.
More than 21.9 million commercial passengers flew through the airport last year. That's an increase of 4.7 percent over 2009 and eclipses the previous record of just over 21 million set in 2007.
Through December, the airport recorded eight consecutive monthly records. July was the busiest month ever at BWI.
More than half of last year's passengers flew on Southwest Airlines, the airport's largest carrier.
Gov. Martin O'Malley says in a statement that the record traffic shows that the state's investments in its airports and focus on customer service are paying off.