Once aircraft are added to Leon you need to add appropriate functions (crew positions) to it. It is very important part of the system because it will allow you to add ratings, assign crew to flights and create duty on aircraft.
In this section select an aircraft type in the filter and mark needed checkboxes.
You can see 5 columns in this section:
You can assign function to each part of you business (Flying crew, Maintenance, Ground) by going to different tabs in the top of the screen.
Positioning tab will allow you to assign functions that do not calculate FDP but duty only (PSN) or neither FDP nor Duty (PAD).