As the airlines continue to struggle, your frequent-flier program may be in flux. Here’s what you need to know.

Delta recently launched a new system for redeeming miles, so the days of 25,000 or 50,000 miles for a domestic ticket are gone.

This new system is in three tiers: “low level” starting at 25,000 miles; “medium level” starting at 40,000 miles; and “last open seat,” which is a minimum of 60,000 miles as long as there’s an available seat.

Bottom line: It’s likely that those low-level seats are going to be extremely limited, so in the long run, you’ll use more miles to get a ticket.

The good news is Delta has dropped its surcharge to redeem your miles.

American Airlines will change its policy on January 1. Instead of earning a minimum of 500 miles each way, fliers will only earn awards on the actual number of miles traveled.

That’s especially going to affect short-haul fliers. Instead of earning 500 miles to fly from New York to Washington DC, you’ll only get about 200.

And, Virgin America has a new plan called Elevate. You earn five points for every dollar. So you get rewards based on how much you spend, not how far you fly.

You can do the math on how that’s going to help travelers with discount tickets.

For more, check out Helpful Frequent Flier Web Sites as well as Frequent Flier Follies: Why Airlines Don’t Make Good Banks.

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