If a company has more than one main base where the staff is located then you can define in Leon more bases and assign a proper one for the crew and other staff members.
Click icon and in section General settings (at the bottom of the page) you can define bases. After re-logging right next to your name you will see a drop-down box with the list of bases.
Go to > Fleet and edit a particular aircraft - at the bottom select the right base.
Click icon 'Users', edit the profile and assign a base.