travel/reservation code

[Muz]

Does anyone know of any open source java software/code libraries for
doing travel/airline reservations?

I'm looking for a typical airline (hotel, car rental?) type of
reservation system that I can customize for an incubating travel
business. Even if it's just the model layer, that would be helpful - I
can add the UI and persistence layers. I'd sooner not have to design &
code the person/airplane/schedule/flight/ticket/reservation/room/car
logic from scratch.

It would obviously have to be much more basic than your typical
internet travel agent site runs, but a little more functional than the
typical university computer science assignment.

thanks in advance
M.