As SFO (San Francisco) has been my primary airport for most of the past 7 years, I figured I would start with United, which is the only of the “Big Three” U.S. airlines (United, American, Delta) to have a hub there.

United generally has one of the better online award travel search engines. You have access to almost all of the Star Alliance airlines, and it’s very easy to use. Furthermore, Star Alliance is the largest of the three major airline alliances, which will allow you award flights to almost (not here) anywhere in the world.

To search, all you need to do is check “Search for award travel” on United.com:

There are two types of economy awards on United: Saver, and Standard. Saver awards cost half as many miles as Standard awards , and are generally how you want to use your miles. If there are no saver awards available for your date and you have some flexibility on dates, check other dates. Standard awards should really only be used if you have no flexibility on dates and you don’t want to pay for the flight, but it’s not a very good use of your miles.

United used to display Standard and Saver awards in separate columns, but now they combine them, always listing Saver award space first. For example, here is an award search from Boston to Kathmandu, with saver award space on a routing that combines Lufthansa and Thai Airways, and Standard award space on a routing that combines United and Air India:

In this situation (aside from the fact that Lufthansa and Thai Airways are far better than United and Air India), you want to choose Saver award. Of course, it’s always important to look at the taxes and fees associated with each award. These are generally either charged by the airports that the flight passes through, or sometimes by the airline under the misleading name of “fuel surcharges.” In some situations in which one award might charge you several hundred dollars in additional taxes and fees to book, it might not be a good idea even if it’s less miles. Of course, in this situation, saving $20 in taxes and fees with the second option isn’t worth the extra 42,500 miles.

The problem with United’s online award search:

As I mentioned earlier, United shows most, but not all Star Alliance flights. In particular, there are two airlines that get left out. The first, Shenzhen Airlines, is an airline that you or I will likely never fly unless we live in southern China. The second, Singapore Airlines, is generally considered one of the best airlines in the world, and connects major cities all over the world to Singapore. You do not want to miss a chance to fly Singapore Airlines for free.

While All Nippon Airways (ANA) is generally considered to have the best search engine for Star Alliance availability (in terms of yielding the most results), it’s also extremely difficult to use, and I wouldn’t recommend it for beginners. Instead, to make sure you’re not missing out on Singapore Airlines award space, I would recommend using the search engine for Aeroplan, the loyalty program of Air Canada. (Note that you will need to create a frequent flyer account with Aeroplan first before you can search).

Here’s an example of United’s award search engine showing no nonstop flights between Hanoi and Singapore:

While this itinerary isn’t terrible, it still is frustrating to not fly nonstop between two cities that are so close to each other. But here’s Air Canada’s search engine showing that there is indeed a nonstop flight on that date on Singapore Airlines:

You don’t have to worry about the 20,000 miles displayed next to the award; since you are booking it with your United miles, you’ll use the United rate for one-way travel in Southeast Asia (17,500 miles). You just have to call up the United MileagePlus service center and have them book the award for you.

“OK, but I don’t plan on flying anywhere near Singapore, so can’t I just search United?”

In theory, yes, but given that Singapore Airlines operates five fifth freedom routes (which is when an airline from one country transports passengers between two other countries), it’s often still important to check.

For example, if you were to use United’s award search engine to look for flights from Houston to Moscow, you would see that the fastest way to get there with your miles is by flying United from Houston to Frankfurt, then making a connecting flight to Moscow on Lufthansa:

However, by searching on Air Canada, you’ll see that you can fly nonstop from Houston to Moscow on Singapore Airlines:

Singapore Airlines offers the following fifth freedom flights: (flights that depart the US and go to a country that’s not Singapore)

New York (JFK) to Frankfurt (FRA)

San Francisco (SFO) to Hong Kong (HKG)

San Francisco (SFO) to Seoul (ICN)

Los Angeles (LAX) to Tokyo (NRT)

Houston (IAH) to Moscow (DME)

So if you think there’s a chance that one of those flights might be of use to you on your trip, it’s worth going beyond the United search engine to look for Singapore Airlines award space.

Pro tip: People often use “nonstop” and “direct” interchangeably when describing flights. They are NOT the same thing. A nonstop flight is just what it sounds like – it flies from one city to the other without stopping at any cities in between. A direct flight may stop at a city in between, but and then continue on using the same aircraft and flight number. For example, Singapore Airlines Flight 1 is considered a direct flight from San Francisco to Singapore, even though it stops at Hong Kong on the way. Either the San Francisco to Hong Kong leg or Hong Kong to Singapore leg would be considered nonstop, but not together. In other words, all nonstop flights are direct flights, but not all direct flights are nonstop flights.