If you are referring to returning home from WDW, I would suggest checking in at for your flight at your resort if staying on property. Then I would make sure to be at the airport a min of 1 1/2 to 2 hrs before the flight. This allows for returning the rental car and getting through security. The security lines can be very long at MCO sometimes (it once took me 40 min to get through security).
It's nice to have a little extra time to get a bite to eat near the gate, use the restroom and relax before boarding.
If your talking about your home airport consider parking and a shuttle to the terminal, baggage check-in and security if it is a busy airport.