Other airlines are experimenting with tracking passengers throughout the airport. In the future, if somebody clears security hours before their flight, they might be offered a discounted day pass to the airline's lounge on their phone.
Airlines have yet to find the right balance between being helpful and being creepy. So, for now, most of the data is being used to win back passengers after their flight is delayed or luggage is lost.
"We want to get back to a point where people feel like travel isn't something to endure, but something they can enjoy," says Bob Kupbens, a former Target executive and Delta's current vice president of marketing and digital commerce.
Most passengers select flights based on the lowest base fare. The online travel industry plays up that price sensitivity with sites named CheapOair.com, CheapTickets.com and InsanelyCheapFlights.com.
When airlines try to raise fares, they are met with resistance.
"Customers are very quick to either change travel plans, or use another carrier or not travel at all," says Jim Corridore, an airline analyst with Standard & Poor's.
In the past three years, airlines have tried to hike fares 48 times, according to FareCompare.com. During 29 of those attempts, bookings fell enough that airlines abandoned the increase.
Most fares today don't cover the cost of flying. While the average domestic roundtrip base fare has climbed 3 percent over the past decade to $361.95, when adjusted for inflation, the price of jet fuel has nearly tripled.
When oil prices spiked in 2008, airlines added checked baggage fees. Passengers still bought tickets on the base price and didn't think about the extra expense until the day of travel.
Now airlines are recasting fees as trip enhancements.
Travelers like Nadine Angress, of Mansfield, Mass., see the value. Her recent late-night US Airways flight home landed past six-year-old son's bedtime. She had to work early the next morning. So, for $30 she bypassed the baggage carousel and had the suitcase delivered.