Travel rewards credit cards issued by major banks can be an option for you. Such cards allow earning miles on all purchases and you can redeem them without restrictions. For example, the Discover it Miles credit card will allow you to redeem bonus miles with any airline including British Airways. To redeem miles, you simply need to buy a ticket with the card and then log in to your online account to redeem your miles. The Discover it Miles card will reward you with 1.5 miles for every dollar you spend. There is no annual fee and no foreign transaction fees, so you can freely use the card abroad.