try this one ...
I'm going to suggest
www.schedulebook.com ... we used it at a flight school where I used to work before going corporate, and it is not a bad deal. You can set up resources for your plane(s), pilots, etc., then give anybody you want an access code and control their level of access ... i.e., can they schedule something, or just view it, etc. It isn't a perfect interface, but I have tried several online scheduling programs, both aviation-specific and generic (this one is the latter, but well-suited to aviation), and this one seems to have the fewest major flaws and be the least difficult to understand.
Hope this helps.
Tailwinds,
R