It 'saves' a bunch of stuff, when 'legitimate'.
Compulsory employer super contributions (you are paying those for your casual employee pilots, aren't you)
Obligations to the tax office (you have made your casual employee pilots fill out tax declarations and you've submitted them to the ATO, haven't you)
WorkCover (you've said your casual employee pilots are covered),
Access to a pathway to become a permanent employee (you have explained that pathway to your casual employee pilots, haven't you)
Long service leave (casual employees accrue long service leave entitlements in some Australian states and territories - you're across that and keeping track of your casual pilots' LSL entitlements, aren't you).
Casual loading (you are paying at least the casual pilot award rate, aren't you)
Etc, etc...