Airfare Advice for Mardi Gras??

Sounds like your only question concerns tryign to find lower fares. I haven't checked, but these general rules apply to airfares in most situations.

1. If you try to buy a ticket too far in advance, you can pay too much.
2. If you wait until too late, you pay way too much.
3. Flights filling up for a popular time, and having less discount seats available is one way prices can be high, but it is not the only way. Airfares rise and fall all the time based upon the season you are trying to purchase them, fuel prices and other factors. So, there is some chance prices might go down after Thanksgiving, after the airlines quit bringing in lots of cash. There could be a time where the airlines offer sale prices in early December or after January 1, when demand goes down . However, at some point you risk price could go up as planes fill up to New Orleans. However, on plus side, that time of year is not usually a high demand time for country as a whole, which might be a slight help.
4. All the airlines except Southwest can be priced through using something like expedia or travelocity. Sometimes you can save 10$ or so by going through airline's own website, but to get general idea of prices expedia is fine. You have to price Southwest on their website. There are options on expedia or maybe travelocity or orbitz, or all 3, to find out what the cheapest fare is if you can fly whenever. That can give you some idea of the best you can ever do. If the fare being offered around Mardi Gras is close to that, you may just have to pay that much.
5. You can consider hotwire or priceline to take an un-named airline at an unspecified hour for less money, or to bid on a flight.
6. Expedia and all give option to price nearby airborts, but they are rarely much cheaper from what I've seen.
7. Airline prices are higher that what they were a few years ago when they were all losing lots of money and few people were flying. Absent a disaster, I wouldn't expect those prices being available again in near future.
8. Wait until after Thanksgiivng and keep chcking places like expedia and Southwest.