However, the total miles that the member has accumulated so far will not expire.

Northwest and Continental, for example, insist that miles do not expire.

If 25,000 miles had expired, he said, the cost to reactivate them would be about $300.

With some exceptions, Northwest's program requires 25,000 miles flown for similar perks; miles expire after three years.

And one of the other nice things about the donation is that those miles never expire.

The Mileage Plan program has no membership fee, and accumulated miles never expire.

Redeemable miles do not expire, provided that there is account activity within the previous 18 months.

This is as opposed to some other airlines where as long as you keep flying once every two years, your miles will never expire.

Or even some airlines like Delta Airlines where your miles never expire.

He accumulated substantial mileage at a time when miles did not expire.