Welcome aboard, Kathleen! What a great way to end the summer, by taking a magical family cruise on the Disney Fantasy!
Disney's ground transportation between the port and the airport is a wonderful service. Since Disney takes care of all of the details, your family can simply sit back and relax. Unfortunately, once they drop you off at the airport after your cruise, you would be there with not much to do for quite a large part of the day if your flight isn't until that evening.
Another option is to rent a car at the port and head over to the Walt Disney World resort for a few hours, later returning your car at the airport. You could make lunch reservations at one of the great
dining spots at Downtown Disney or in one of the resorts. Chef Mickey's, 1900 Park Fare, Cape May Cafe and a few others offer fun character meals outside of the parks, so you don't need to buy a park ticket to enjoy these spots.
Downtown Disney can keep a family entertained and well fed all day and night too! Perhaps a few games of bowling together at the brand new
Splitsville would be a fun way to spend your day!
If you're going to be that close to the Walt Disney World resort, I say don't waste your day at the airport! Rent a car and pack in a few extra hours of Disney fun before you head back home, Kathleen!
Let me know if I can help with any other questions as you continue to plan!