United Airlines’ best loyalty perks will soon be reserved for its cardholders. Is the card worth it?

Frequent flyers who hold a United Airlines co-branded credit or debit card can soon earn up to twice as many miles as noncardholders, effectively rewarding the airline’s biggest spenders....

Frequent flyers who hold a United Airlines co-branded credit or debit card can soon earn up to twice as many miles as noncardholders, effectively rewarding the airline’s biggest spenders.