Some info about Allegiant Air that you need to be aware of...Yes, Allegiant Air flies to Orlando but NOT into Orlando International Airport (MCO) but instead flies into Orlando/Sanford Airport (SFB). Now you might ask "So." Well, SFB is located 30 -45 minutes North of MCO. If you were planning to take advantage of Disney's Magic Express, you can't. Disney's Magic Express only leaves from MCO and not SFB. I used to live in Virginia before moving to South Carolina, and we were looking at taking Allegiant Air one time. Yes, the initial flight price is cheaper, but by the time you add on needing a rental car or taxi, fuel taxes and A LOT of miscellaneous fees, it was cheaper to fly into MCO instead of SFB.
So, if you want to fly Allegiant Air, remember these things:
1 - They don't fly into MCO but instead SFB
2 - Disney's Magic Express does NOT go to SFB
3 - Will need a rental car or pay a taxi fee to go to your hotel
4 - Read the small print because a year ago, they used to charge a lot of hidden fees that in turn do not make them the cheapest ticket
I am not sure what dates you are traveling to WDW but I just looked up on Orbitz.com for two to fly from Austin, TX (AUS) to MCO in the middle of December for a week and found Delta for $269/person with free cancellation and one stop or JetBlue for $332/person with free cancellation and non-stop.
I hope this helps some....