After nearly missing a flight due to mismanagement of time (by me), we aim to be walking in the doors of the airport at least 2 hours before a domestic flight. At least.
At MCO, every time we have been FORCED to go through the family line, whereas at different airports we can choose a different line if we wish to, even though we do have a child. We have flown a lot, and even if each of us might have a bag or two, we know what to do and don't need a line with lots of first-timers. But at MCO we have been outright denied access to the normal line, and I won't even get into the TSA person who laughed at the concept of a child being a frequent traveler (it didn't help my case that he flustered me so much I dropped one of the things I was holding while talking to him).
The family line is long. Long long long. At least, when we've experienced it during a mid-December, a later-September, and a mid-February, it's been long long long.
So there's no chance you would find my family dropping off the car at 4 for a flight that soon. If you haven't been there, know that the elevators to get up to the baggage drop areas can be jam-packed, and you might have to wait several elevator cycles just to get into one. That's been our experience using the elevators near the National area, at least. We have never gotten onto the first elevator that showed up, and generally have to wait for several elevators to go before there is room for the 3 of us and our bags.
Every step of the way at MCO can take time, and so we have been dropping off our car at the 3 hour mark.
Sure, that might mean that you'll be there for ages, if you hit a lull for drop-off, elevator use, and security, but after our experience almost missing that flight, I'd rather be bored at the airport for nearly 2 hours than be running to the gate with shoes flapping and pants falling down b/c you couldn't put your belt back on!
Don't forget that you'll also need to gas up the car on the way to the airport.