JLR,
I have the gold Delta Amex. credit card. This allows me to discount the flight costs by using the pay with miles feature. This card also waives the baggage fees.
Look on Delta's website, you can apply for the credit card and get a substantial miles deposit to your Delta frequent flyer account. The first year's fee is waived. You can cancel the card within a year so you don't have to pay the annual fee for the second year.
The website will also explain the pay with miles feature. I maintain the card because the annual fee is less than the baggage fees when DW and I fly Delta who is the primary carrier at Bangor airport.
I hope that this is helpful for you.