Hi,
"Flying" indicates that the flight has departed. You may see "on time" or "20 minutes" below the word "flying" to indicate whether the flight is on schedule or delayed by, in this example, 20 minutes.
If the status shows "scheduled" it means either that the flight is expected to arrive or depart at the time listed or, in some cases, that we do not have actual status data for that flight. I hope that helps.
As the feature is still in Beta, we might consider substituting the word "departed" for the word "flying" and see if that helps avoid any confusion