We had an 11:50am flight last time and even with the ship being delayed to port that morning by an hour, we were at MCO in plenty of time.
The cruise before that our flight wasn't until some time between 3 & 4pm and we spent too long waiting around at the airport. I will try to keep it around noon, but certainly not before 11:30 -- you just never know what the weather will have in store for you.
It's better to be safe than sorry.