Delta, American Match Frequent-Flier Offer

Delta Air Lines Inc. and AMR Corp.’s American Airlines matched Northwest Airlines Corp.’s move to eliminate restrictions on the dates when frequent-flier mileage credits can be used for free flights.

The three carriers said their frequent-flier club members will be able to use the credits to fly on any day when seats set aside for the mileage awards remain available. The programs haven’t allowed travel on some holidays and other days when the airlines have high demand from paying customers.