You might want to add your friend/parent/relatives flight
In order to differentiate them from your flights to theirs you have 3 ways to mark these flights:
1. Assign these flights to the "People" tab. To learn more about tabs in "Trips" check this article.
2. Add a new note in "Travel docs" widget. You are able to write the name of a passenger in the title of this note and attach a file, if needed.
3. Re-name the trip. You will be able to see whose flight it is just by looking at the trip card. You can see how to re-name your trip after reading this article.