If you fly Frontier Airlines only, their card can be a good option. But if you choose different companies when plan your trip, we can recommend you to consider a general credit card with rewards program, not an airline-branded credit card. For example, the Discover it® Miles can be a good option for you. There are no annual fees and no foreign transaction fees. Every dollar you spend on this card will bring you 1.5 miles. There is no sign-up bonus but all miles you earn the first year will be matched at the end of your first year (provided you are a new cardmember). So if you, for example, earn 50,000 miles during the first year, Discover will turn them into 100,000 miles. Earned miles can be redeemed with any airline, provided a ticket is bought with the Discover it® Miles card.