For some passengers, this is a big attraction, because it means not only a chance to board early but also a chance to check a bag free rather than paying a charge.

FORBES: Will American's New Boarding Process Work? It Failed At Virgin America.

Southwest remained profitable even when fuel prices spiked, thanks to brilliant hedging, and has launched a series of moves to raise revenue without charging to check a bag, which really irks people.

FORBES: Southwest Shares Are Tempting But Airline Stocks Usually Don't Fly

And it's just every other bag that comes through is a bag check.

NPR: Airport Security Marked by Hassles

The suspect had a shoulder bag and went through the normal check-in process with his passport and U.S. visa scanned, Demuren said Sunday.

CNN: Obama orders review of flight screenings