How U.S. airlines make $7 billion a year from checked bags

For decades, most bags flew for free, but in recent years fees have surged, boosting the bottom line of the nation’s carriers.

“There’s a lot of complexity behind what goes into ensuring that a passenger’s bag arrives at their destination with them,” said Kirk Pilliner, general manager of Baggage Operations for Delta Air Lines.

At Atlanta’s Hartsfield-Jackson International Airport, more than 30 miles of conveyor belts, an army of 2,000 workers and a fleet of airport tugs ferry bags from the terminal to the aircraft to ensure passengers are reunited with their luggage at their destination.

U.S. carriers hauled more than 470 million passenger bags last year.

So what steps do airlines take to prevent lost luggage and how does Delta Air Lines move 100,000 bags a day through the world’s busiest airport? CNBC got a behind-the-scenes look at at Delta’s baggage operation in Atlanta to find out.

Watch the video to learn more.