Delta Air Lines is changing the perks for its co-branded American Express credit cards in a move that divides its members into two camps: those motivated by free travel and those motivated by exclusive amenities.

The Atlanta-based airline, which is the dominant carrier at Minneapolis-St. Paul International Airport where Delta boasts a large business-traveler base, announced the changes Monday.

After a year of research with current and prospective cardholders, Delta said the tweaks will give people more of what they want. Co-branded credit cards have become a significant source of revenue for airlines with travelers jumping at the chance to rack up more miles.

"Each card is tailored to what our customers have told us is most important to them — ranging from ways to earn even more miles to travel perks along the way," Sandeep Dube, Delta's senior vice president of customer engagement and loyalty, said in a statement.

Delta said its blue and gold card members are more cost-conscious and less-frequent travelers who care most about earning miles to offset ticket prices. Its platinum cardholders are loyal to Delta, but want to get to their travel rewards quicker. And its reserve members want to earn elite status faster so they can enjoy the luxury amenities.

After the changes go into effect in January, the airline's gold, platinum and reserve cardholders will earn more points on daily purchases, such as restaurants and supermarkets.

"Delta is clearly making a move to get consumers to put more everyday purchases on their cards," said Richard Kerr, a loyalty editor with the Points Guy, a website dedicated to analyzing travel points and programs.

There are, of course, trade-offs. Most will pay a higher annual fee. (Blue cardholders are the exception as that card's annual fee will remain $0.)

The annual fee will increase from $95 to $99 for gold, from $195 to $250 for platinum and from $450 to $550 for reserve.

Gold cardholders will no longer be able to access Delta's Sky Club lounges for a fee or use their purchases toward Medallion Qualifying Dollar (MQD) waivers, which is a path to elite status. Delta declined to say exactly how many of its gold members used these two perks, but said less than 5% used the Sky Clubs and less than 1% used the MQD waiver.

Platinum members will still have lounge access, but the fee per visit is increasing from $29 to $39. Delta also is giving these cardholders either a Global Entry or TSA PreCheck fee credit.

Cardholders of the airline's top-tier, reserve, now have access to the exclusive American Express Centurion Lounge, which opened in a limited number of airports worldwide but not at MSP. They also will receive two one-time guest passes to Delta's standard Sky Clubs each year. Reserve cardholders can also earn a 15,000 medallion qualifying miles (MQM) boost four times a year, which is twice as often as currently offered.

"I like some of the creative strategies for the reserve," Kerr said. "I don't particularly like the increased annual fees, but I don't really see anything cynical in the changes either. The card is definitely a value-add for a Delta road warrior."

A more detailed breakdown of the differences of each card can be found on Delta's website, newdeltaamex.com.