Travelers who live in the United States are understandably familiar with domestic airlines. However, these carriers also partner with global alliances, and you don't have to credit your miles to the same airline's frequent flyer program. Foreign carriers often have different rules that can create valuable opportunities to earn free travel faster.

One of the best loyalty programs for Americans is British Airways' Executive Club, which uses a currency called Avios. You can earn and redeem Avios when you fly on Alaska Airlines and American Airlines. Avios uses a distance-based award chart in which short, nonstop flights are incredibly cheap, sometimes as low as 4,500 points one way. And Avios is the cheapest way to fly from the West Coast to Hawaii, at only 25,000 points round-trip.