A Midwestern airport has become the 21st in the country to offer the Transportation Security Administration's PreCheck expedited screening option for qualified passengers.

TSA said PreCheck is now available at Indianapolis International Airport for participating frequent flyer members of American, Delta, United and US Airways, as well as participants in Customs and Border Protection trusted traveler programs like Global Entry.

Participants are identified by a special code embedded into the bar code on their boarding passes, which makes them eligible to be directed to the special PreCheck security screening lane. During the expedited screening, passengers may not have to remove their shoes, or take laptops or liquids out of their carry-ons.

TSA said that with the ongoing expansion of PreCheck to additional airports and airlines, more than 2 million travelers have been processed through the expedited screening option since testing began last fall.