United Airlines is revamping its MileagePlus rewards program to attract more credit card customers while tightening benefits for non-holders. The new structure limits miles earned for non-cardholders, particularly affecting those booking basic economy tickets. This strategy aligns with industry trends as other airlines bolster credit card relationships and as Delta reports an uptick in revenue from premium seating. Despite these competitive pressures, United remains financially robust, anticipating improved earnings in the near future.