Well, it depends. We made a 12:35 flight, barely. We got to the gate just 30 minutes before flight time.
Disney makes it clear that any flight BEFORE 12:30 is an EARLY flight.
IF the ship arrives on time, IF clears customs and immigration in a timely fashion, and IF there aren't any crashes on the highway, and IF there is no backup at security at the airport, you should be fine. But ANY delay could put your flight in jeopardy.
To this day, I do not know what the delay was getting off our cruise, which ended 1-3-04. I do know we lined up at 8:30, and it was 9:15 before we stepped off the ship. The line went thru the Attrium, past Luminieres, and did circles inside Parrot Cay. It kept moving the entire time, just very slowly.
I do know that Disney wants everyone off by 9 am, and I do know that it took until 10:15 on our cruise to get everyone off.
We actually got to the airport at 10:15, but there was a 90 minute wait to pass through security at the airport. I like to be at the gate at least an hour before boarding, we make it 15 minutes before boarding, and 30 before departure time.
I guess Clint Eastwood sums it up best. " Do you feel lucky?" Can it be done? Yes. Can there be problems? Yes. Pushing your flight back past 12:30 greatly increases your chances of making your flight.