Calendar Extension Question

I need to create an interactive calendar for a small flight school. The client
would like to have a calendar on his web site so that a student pilot or renter
can reserve an aircraft on a given day at a given time. I've looked at
Calendar MX pro and it looks like it would probably fit the bill, just to give
ya'll an idea of what I need. Unfortunately, Calendar MX pro does not come in
a Macintosh version. Can someone recommend a Mac compatable program similar to
Calendar MX Pro?