Delta wants customers to spend their SkyMiles, not just save them for free flights

Many frequent fliers delight in saving up their miles for free flights, but Delta Air Lines wants them to spend those miles instead of just amassing them for future vacations.

Frequent flier miles amount to a "giant liability" for Delta, said Glen Hauenstein, the airline's chief revenue officer and incoming president, during an investor presentation Tuesday.

"When you think about how people have traditionally used those miles -- they save them up, sometimes they take their families on vacation, sometimes they save them for retirement," Hauenstein said.

"We have to find new and creative ways for our customers to burn those miles," Hauenstein said. "There are other uses in much smaller increments that you can use to control your experience," such as buying a bottle of champagne in a Sky Club, he said. Using miles for haircuts or massages someday "is not out of the question," Hauenstein said.

The perspective from Delta comes after the airline last year eliminated its mileage award charts from its website, blocking one of the key ways frequent fliers planned for saving miles for a dream vacation.

And it's also part of Delta's effort to extract more revenue from customers who want better service, from first class and extra-legroom seats to other extras.

As Delta works to increasingly convince travelers to pay for better seats, elite frequent fliers are concerned that could mean fewer free seats left for them in first class or Comfort+ extra legroom seats.