It might be that you have added trips on TripIt but they were not imported to App in the Air. Probably, there is not enough information on TripIt for it to import to our App. 

You are able to check it in Settings in our App(Profile tab -> Settings):

This occurs when there is not enough information in your TripIt account to import a flight to our App.

When you tap on “TripIt sync status” you will see what information we need to successfully import it to our App:

For example, “invalid arrival airport” means that you need to add an arrival airport into TripIt for this particular trip.

After you add the needed information for your trip on TripIt, go to our app -> Profile -> Settings -> Sync TripIt now. After a while, the flight will automatically be added to your profile.

After syncing with TripIt, you'll be able to see if everything is okay:

And if you tap on "TripIt sync status", you'll see that the problem is solved.