There are three main airline alliances in the world: Star Alliance, SkyTeam, and oneworld. Why are airline alliances important? Most practically, they’re useful for 1) earning miles; 2) redeeming miles; and 3) offering reciprocal benefits.
1) Earning Miles
Essentially all airlines have their own frequent flyer programs, but miles are usually only worth something if you surpass certain minimum thresholds in a single program. For example, it’s not worthwhile to have 5k miles across 5 different programs (unless you like magazines), but 25k miles in 1 program can usually get you a free flight. How do you deal with this if you fly lots of different airlines?
This is where airline alliances come in. If I fly on British Airways, I don’t have to credit my miles to British Airways Avios–I can instead credit my miles to American Airlines since both are oneworld partners. This means that I can focus on earning miles in one specific program, which makes it easier to reach the minimum thresholds necessary for good redemptions. This also applies to earning miles for status and not just redemption. So your flights within an alliance can all be credited to one airline to help you reach that next tier of airline status on a single airline.
Note that airlines often have airline partners outside their alliances. One notable case of this is Alaska Airlines. Alaska Airlines isn’t a member of any of the three major alliances, but you can often think of them as a oneworld airline since they partner with so many of the oneworld airlines. For example, you can credit Alaska flights to American Airlines and vice versa.
One thing that often takes people by surprise is that mileage earning isn’t consistent across partners. In the past, you earned miles on the legacy US carriers based on miles flown (this has now changed to be based on dollars spent on the major three). For most airline partners, you generally earn a percentage of the miles flown based on your fare class, and many of the cheapest fare classes offer only 25% (or even 0%) miles. So oftentimes it’s worth checking how many miles you’d earn if you credited a flight to a certain partner based on your fare class, but this is getting into a more advanced topic for another post.
2) Redeeming Miles
Want to go to Bangkok but only have American miles? While American Airlines doesn’t serve Bangkok as a destination, their partners do, so you can still redeem American Airlines miles on their partner airlines to get to Bangkok (in this case, your likely options would be Cathay Pacific through Hong Kong or Japan Airlines through Tokyo).
This is probably the best part of airline alliances. If you could only redeem your miles on that airline (which is true of some programs!), then you’d be severely limited on where your miles could take you. But thanks to airline alliances, your miles can take you anywhere the alliance flies (which is essentially any major destination for the three largest alliances).
Again, one thing to keep in mind is that airlines often have partners outside of their alliance. For example, Hawaiian Airlines isn’t a member of any of the major alliances, but they partner with American and United, so you can redeem your American or United miles on certain Hawaiian flights.
3) Reciprocal Benefits
Airline alliance members also generally offer reciprocal benefits to frequent flyers who have status on a partner airline. These benefits are things like dedicated check-in lines, priority boarding, free checked bags, and lounge access.
Lounge access is a favorite of mine and is particularly relevant for international itineraries. For oneworld airlines, if you have oneworld Emerald status (the highest frequent flyer status across oneworld airlines), then you have access to any oneworld First Class lounge on international itineraries. This gets you access to awesome lounges like the Cathay Pacific First Class Pier lounge in Hong Kong or the Qantas First Class lounge in Sydney, even if you’re flying on an economy class ticket.
Note that each airline has different qualification criteria for their own levels of elite status, and those different levels correspond to different levels of alliance elite status. And each alliance has different benefits for different levels of alliance elite status (e.g. Star Alliance Gold, the highest level of status in Star Alliance, doesn’t offer First Class lounge access).
This is just a primer on why airline alliances are practically important for travelers, but if you fly relatively frequently, especially internationally, then it might be worthwhile to concentrate your flying within one specific alliance to reap some of these benefits.
Here are the three main alliances and their members:
Star Alliance: Adria, Aegean, Air Canada, Air China, Air India, Air New Zealand, ANA, Asiana, Austrian, Avianca, Brussels, Copa, Croatia Airlines, EgyptAir, Ethiopian, EVA, LOT, Lufthansa, SAS, Shenzhen, Singapore, South African, Swiss, TAP Portugal, Thai, Turkish, and United
SkyTeam: Aeroflot, Aerolineas Argentinas, Aeromexico, Air Europa, Air France, Alitalia, China Airlines, China Eastern, China Southern, Czech, Delta, Garuda Indonesia, Kenya, KLM, Korean, Middle East, Saudia, TAROM, Vietnam, and Xiamen
oneworld: Air Berlin, American, British, Cathay Pacific, Finnair, Iberia, JAL, LATAM, Malaysia, Qantas, Qatar, Royal Jordanian, Sri Lankan, and S7