Delta Air Lines this week made it a lot harder for frequent fliers to attain the coveted Diamond status by making purchases with their SkyMiles American Express card.

Amex cardholders who chose the qualifying dollar waiver option used to have to spend $25,000 annually to reach the Diamond level, the highest status in Delta's frequent flier program. But starting on Jan. 1, fliers will have to spend $250,000.

As expected, many fliers were very unhappy with the change.

"I don't know personally of very many people who can spend $250,000 on all their credit cards in one year," said Andrew Hiscox of Chanhassen.

Several airlines have trimmed benefits in loyalty programs in the past several years. Announcements such as this, while somewhat of a shock at first, have become less surprising.

Christopher Elliott, the ombudsman for National Geographic Traveler magazine, said if Delta's goal was to make the Diamond medallion more special by reducing the number of people who qualify, it's "mission accomplished." Delta said that it wants to sell 70 percent of its first-class seats to cash-payers, not upgraders, in 2018. In 2015, the percentage was 57 percent.

"Plain and simple, this is a way for Delta to make more money," Elliott said.

In a statement, Delta said, "We understand this is a significant increase, but keep in mind that the Medallion Qualification Dollars waiver to qualify for all of the best-in-class benefits of platinum, gold and silver medallion status will remain at $25,000."

Some customers are happy with the change — the truly elite fliers who fly 125,000 medallion qualification miles and spend at least $15,000 paying for Delta flights. Delta said that feedback from Diamond medallion members drove the change in the diamond waiver adjustment.

Delta had so many customers who had attained Diamond elite status using the $25,000 Amex waiver instead of spending $15,000 only on Delta flights that hardly anyone felt special anymore.

"It's disheartening when you're No. 38 on the list of 50 people hoping for an upgrade into first class," said Jason Steele, a credit card expert at "Or when it was standing room only in the Sky Clubs."

If the dismay vented on Twitter is any indication, this was the last straw for some of Delta's frequent fliers. "Bye bye Delta. I'm taking my biz elsewhere," tweeted one current Diamond medallion and Delta Amex customer.

Travel experts are divided on how easy it will be for many consumers to switch to other airlines. Elliott thinks consumers should buy the lowest-price ticket with the most convenient terms possible, regardless of the airline.

Peter Greenberg, CBS News travel editor, said it's not always possible to switch carriers in airports with a dominant hub. "The consumer has little recourse now that we're down to only four major airlines," he said. "There was no antitrust legislation in the last two administrations and now we're paying the price."

On the other hand, consumers still have plenty of choices internationally and in places such as San Diego, Boston or St. Louis, which have no hubs. "You can fly to New York, L.A. or Chicago and have a lot more choices on international flights," Steele said.

Delta said that no other card benefits or medallion qualifying requirements have been changed.