IndyGo is also encouraging riders to plan ahead and allow extra time for their July 4 travel because special events and road closures will cause detours and delays.

U.S. airports have security checkpoints to keep weapons off airplanes. But airports have public areas where people shop, check bags and line up for TSA. The public areas create vulnerabilities.

AAA projects more than 1 million Indiana residents will travel during the holiday, a 1.3 percent increase from one year ago.

American and United - the airport's two major carriers - reached agreement with O'Hare to build a new runway, which will complete a decade-long modernization project.

Nearly one in three Americans will take a trip this holiday season, with 100.5 million expected to journey 50 miles or more from home.

AAA estimates that cheaper gas prices have saved Americans more than $115 billion on gasoline so far this year, which works out to more than $550 per licensed driver.

An Associated Press report published Tuesday drew a connection between rising airfare prices and the decreasing number of major airlines. Thanks to mergers, there are only four major airlines left flying the skies.