United Continental Holdings, the world’s largest airline by passenger traffic, joined Delta Air Lines in a move to reward elite passengers based on both spending levels and miles traveled.

Starting in January, United passengers must spend $10,000 and travel 100,000 miles or 120 segments in order to gain the top status of Premier 1K, Chicago-based United said in an e-mail to MileagePlus customers.

Delta, the world’s second-largest airline, made the switch to a similar loyalty program in January this year. United’s move could see all major airlines eventually migrate in that direction, said Jay Sorensen, who runs IdeaWorks, a Shorewood, Wisconsin-based airline consulting firm.

“At some point we’re going to see miles go the way of the buggy whip and they will no longer be part of frequent flier programs,” Sorensen said. “This is going to upset people who are miles junkies tremendously because they really have tapped into this awkward method of measuring the value of a customer.”

United shares rose 1.1 percent to $32.44 at 11:31 a.m. in New York. Through yesterday, the company’s stock had increased 37 percent, trailing a 41 percent increase in the Bloomberg U.S. Airlines index.