Those are some crazy connections. I haven't used Carnival's Fly Aweigh program for several years. In the FAQ section on their site they mention Custom Fly Aweigh Services in a sub link
Here.
I usually book my air independently if I have to fly. They do have some wording about being responsible to fly you to your destination, including additional flights and/or hotels at no cost to you if you use the service from what I understood.
Dwayne