If you do not stick strictly to Aer Lingus Airlines, their credit card is of no use for you, as you will not earn rewards when flying with other airlines. What is more, it gives only 1x Avios on all other purchases. You will need to fly a lot to earn enough miles for award Aer Lingus flight. If you want to earn miles and redeem them with different airlines, the Discover it® Miles credit card can be an option for you. The card allows earning 1.5 miles on all purchases. All the miles earned during the first year will be matched at the end of the first year (if you are a new cardmember). For example, if you earn 30,000 miles, you will get 60,000 miles. You can redeem earned miles with Sun Country or any other airline. This card also comes with no foreign transaction fees, so you can use it abroad.