United Airlines program to reward big spenders

United Airlines is taking another step in combining its frequent flier program with Continental’s. But the changes that may get a mixed reception from travelers.

United is boosting rewards for people who buy some of the most expensive tickets, instead of just those who fly the most miles. The airline says it’s trying to make those expensive tickets more attractive.

Miles in the combined program will expire after a year and a half. That will not be a change for United travelers. Continental had no expiration date, although accounts could go inactive after a year and a half if no new miles were earned.

United and Continental merged almost a year ago into United Continental Holdings Inc. United says it will launch the combined frequent-flier program early next year.