You can probably do a whole lot better buying airfare on your own. Plus, that way YOU decide what flight is best for you, not letting
DCL decide. I think there's a way to change the DCL-chosen flight but they charge an additional fee pp. Someone else can explain this better.
Chances are, DCL will fly you down the same day as your cruise. Which usually means waking up at 4am, and taking a huge risk if you have any mechanical or luggage delays. Even if all goes well, unless you're used to waking up that hour, you'll all be deliriously tired that 1st night. Most Dis-ers agree it's much smoother to fly down the day before. Even if it's the night before (after school/work), you still get a good night's sleep and just have to make your way to the port in the morning.
There are plenty of reasonable hotels near MCO and can get something very nice from Hotwire for well under $100. jmho