Here are North America's best airline rewards programs, according to new ranking

Airline loyalty programs and credit cards are used by tens of millions of Americans every year to book vacations and travel for the holidays, but which ones provide the most value? 

Point.me, a paid service that helps travelers book trips using rewards and frequent flier miles, has ranked the top airline rewards and loyalty programs both worldwide and in North America. 

The scores were based on the ease of earning miles from non-flying methods (like dining out and other purchases); the value you’ll get for those miles; the ease of booking a reward flight; the frequency of award availability; flexibility in routing rules (can you book a stopover, for example); change fees and policies; hold policies, and customer service when it comes to booking. 

United Airlines was ranked as the top U.S. airline for airline rewards and frequent flier miles (Photo by Kevin Carter/Getty Images)

According to Airlines for America, there are nearly 30 million airline credit card holders in the U.S. alone, and point.me says loyalty programs are multi-billion dollar businesses. 

RELATED: Southwest Airlines Companion Pass offer: What to know about buy-one-get-one flights deal

"With major credit card programs offering dozens of airline transfer partners, it can be difficult to know which loyalty programs are best," the report’s authors wrote. 

Point.me’s latest rankings come amid a U.S. Department of Transportation investigation into rewards programs at America’s four largest airlines over "potential unfair, deceptive, or anticompetitive practices." 

RELATED: Feds open investigation into major airlines over popular rewards programs

American, Delta, Southwest and United Airlines have been asked to hand over records with detailed information about their rewards programs, practices and policies. 

The DOT noted that many airlines reserve the right to change the terms of their rewards at their discretion. 

RELATED: United Airlines flight diverted to Memphis over 'severe turbulence' that left 7 injured

"These programs bring real value to consumers, with families often counting on airline rewards to fund a vacation or to pay for a trip to visit loved ones," U.S. Transportation Secretary Pete Buttigieg said. "But unlike a traditional savings account, these rewards are controlled by a company that can unilaterally change their value. Our goal is to ensure consumers are getting the value that was promised to them, which means validating that these programs are transparent and fair." 

Best airline loyalty programs in North America

Here are point.me’s best airline rewards programs in North America: 

• Air Canada Aeroplan
• United MileagePlus
• American Airlines AAdvantage
• Alaska Airlines Mileage Plan
• JetBlue TrueBlue
• Southwest Airlines Rapid Rewards
• Hawaiian Airlines HawaiianMiles
• Delta SkyMiles
• Allegiant myAllegiant
• Spirit Airlines Free Spirit
• Frontier Miles
• Sun Country Rewards
• WestJet Rewards

Best airline rewards programs worldwide

Point.me ranked the following airline loyalty programs as the 10 best in the world: 

1. Flying Blue (AirFrance and KLM)
2. Air Canada Aeroplan
3. United MileagePlus
4. (tie) British Airways Executive Club
5. (tie) Virgin Atlantic Flying Club
6. American Airlines AAdvantage
7. Alaska Airlines Mileage Plan
8. Qatar Airways Privilege Club
9. JetBlue TrueBlue
10. Avianca LifeMiles