Let's be realistic, though ... nobody in their right mind would be flying planes into the hurricane area, so you're left only with the planes currently on the ground at the time. What's that ... 20 or 30 planes, because NO is a destination, not a hub.
At most you're going to get a few thousand people out (and they did), and most of those are people who were at the airport to begin with. You wouldn't be able to touch the main body of people still in the city.
No, the only way to get a bunch of folks out quickly would have been by packing them onto trains, and that clearly did not happen.
What about the idea I posted earlier: making the "incoming" sides of the freeways be two way traffic reserved for emergency vehicles and either incoming busses of >20cap or outgoing busses of >20pax? There are many thousands of busses within a few hundred miles of NO, and a dedicated bus line on the freeways would have allowed them to move effectively.