Frequent fliers, fasten your seat belts.

Delta is making a major change to its frequent flier program, moving from mileage-based awards to a dollars-based program. That means you will earn free flights based not on how far you travel, but rather on how much you spend on fares.

Delta says its aim is to better reward “premium travelers” — airline-speak for the folks who pay higher last-minute fares. They will earn more points under the new program, while leisure travelers who find bargain fares will earn fewer.

Delta’s changes took effect Jan. 1.

Meanwhile, former AirTran customers are now part of the Southwest frequent flier program, which awards points based on the fare type and dollars spent.

Here are the basics for frequent fliers of Atlanta’s two largest airlines, Delta and Southwest:

Delta’s 2015 SkyMiles program

SkyMiles program status…Miles earned per dollar

General SkyMiles members…5

Silver…7

Gold…8

Platinum…9

Diamond…11

*Delta SkyMiles credit card holders will earn an additional 2 miles per dollar on Delta purchases with the card

Examples

General SkyMiles member, booking $300 Atlanta-New York roundtrip ticket

Old program: Earns 1,518 miles (roundtrip distance)

New program: Earns 1,500 miles ($300 x 5)

Diamond elite SkyMiles member, booking $550 last-minute Atlanta to Dallas roundtrip ticket

Old program: Earns 3,289 miles (roundtrip distance)

New program: Earns 6,050 miles ($550 x 11)

Redeeming miles

Starting in 2015, there are five tiers to redeem miles for roundtrip flights, depending on availability for each flight.

For travel within the U.S. and Canada, excluding Hawaii:

25,000

35,000

40,000

50,000

65,000

Southwest Rapid Rewards

Points earned per dollar (for each type of fare)

Fare type: Wanna Get Away…Anytime…Business Select

General Rapid Rewards members: 6…10…12

A-List status: 7.5…12.5…15

A-List Preferred status: 12…20…24

Examples

General Southwest Rapid Rewards member, booking $100 discount Wanna Get Away fare

Earns 600 points ($100 x 6)

A-List Preferred member, booking $220 extra-perks Business Select fare

Earns 5,280 points($220 x 24)

The number of points needed for a reward flight depends on the fare, and can vary based on the route, time and day of travel, demand, fare class and other factors.