Until Sept. 30, United Mileage Plus members can combine two existing bonuses to rack up a total of 2,500 bonus miles for booking and checking in online at united.com.

As has been the case for a while, members can earn 1,000 miles for booking online. From there, a member can earn 500 more miles for each segment checked in using of EasyCheck-in Online, up to 5,000 miles for 10 segments during the promotional period. United will throw in an extra 500 miles for booking and checking in online on the same itinerary.