There are two websites that all frequent fliers should be familiar with: AwardWallet and ExpertFlyer. The former helps you track your various frequent traveler information (car, hotel, and airline), the number of miles you have, expiry date, and so on. ExpertFlyer lets you search for award fare, which is particularly important when trying to book award tickets or look for routing to use Global Upgrade Certificates from Delta (or Systemwide Upgrade Certificates from American Airlines).
There are two different types of AwardWallet accounts: Free or Plus, and a brief difference between the two can be found below. The biggest perks are that having a Plus account is that you will be able to refresh accounts in parallel and that you will be able to see expiry dates of miles/points. This means you can plan any necessary purchases/trips to make sure your account stays active and your points stay safe. If you sign up with this invitation link [affiliate link], I would appreciate it!
As you can see, AwardWallet Plus also shows special codes attached to accounts: the companion fare for my Alaska Airlines credit card, for example. It also shows my Hyatt Suite Upgrades and Starwood Suite Night Upgrades, and when they expire. Plus only costs $5 every 6 months, which is very reasonable for what you get.
On the other side of things we have ExpertFlyer, which lets us find find particular equipment (for example, those of us who have a fascination for 747-400s ;)), route selections that allow for use of System Wide Upgrade certificates (more on that below), and other information that isn’t as easily viewed at other locations. I opted for Basic as I don’t need to search too often, and while flexible searches would be nice, I can live without it.
To search for routes that would allow me to use my Global Upgrade Certificates, for example, it is as simple as clicking a checkbox! Note that each search will use two queries: one for the departure and one for the return.
The Seats column identifies how many eligible seats are available for the particular code (Z, in this case), and the aircraft type is also shown. ExpertFlyer doesn’t allow direct booking with this information, though, so you will have to find the same fares on the respective airline website to do that. I usually call Delta as it allows application of the upgrade certificate at the time of booking.