Here's an update to all the rules with the change in red.
There are at least 5 ways to use their loyalty program benefits to pay for part or all of your tickets:
- Shop with miles
- Miles + cash
- Pay with miles
- Companion certificates
- eCredits
Shop with miles: You need to have enough miles to pay for the entire trip. If you use miles, you can’t combine them with any other options.
Miles + cash: Good to use if you almost have enough miles. Essentially, you’re buying more miles to combine with what you already have.
Pay with miles: Requires a Delta Gold card or higher. You can cash in some of your miles to reduce the amount due. Not all fare codes are eligible for pay for miles, and the number of seats for their use may be limited.
Companion Certificates: Delta Reserve American Express ($550/year) gives you a coupon good for a companion coupon that can be used with any type of fare. Lesser cards are restricted to the main cabin fares. To use a certificate, you have to go to your profile, select the certificate menu, and click the box for companion coupon BEFORE you select your trip dates and times. They can only be used for round trips in the continental US. After you select your flights and your companion, you can add eCredits to reduce the amount due.
They have an expiration date that applies to the dates you fly, not when you book it. The number of seats available for Companion certificates is definitely limited. To use them, book as early as you possibly can.
eCredits: eCredits are issued when you make flight changes/cancelations that Delta won’t refund to the original payment method. To use them, book your flights and click the
Use eCredits button above the payment window. You can add up to 5 eCredits. Even if multiple travelers are on the same booking, the eCredits can only be applied to the price of the ticket for the person that owns them. If multiple travelers on the same booking have eCredits, they have to be entered under the name of the owner. If the amount of the eCredit more than the owner’s ticket, you will be issued a new eCredit for the difference. So eCredits can be used in combination with Companion Certificates, but the companion’s eCredits will only go toward the fees/taxes, and a new eCredit will be issued for the difference.
Of course, Delta is free to change the rules at any time.