I've flown allegiant airlines about 9 times in the past 2 years. 7 of those flights were delayed. Once, I even missed a connecting international flight because the allegiant flight was delayed by two hours. And now they are also charging carry on baggage fees. Their track record is pretty miserable. They are an inexpensive airline, so long as you are traveling by yourself, you don't need luggage, and you can fit under the seat in front of you. Have you tried to use their website? It's a series of trickery, to try to nickel and dime you and drive up your costs. The website will automatically checks boxes for priority boarding and seat assignments and for insurance. If you don't catch it before paying you've been officially screwed. It's ridiculous.
Once you arrive at the airport, if you didn't pay extra for assigned seats or priority boarding, then you wait for them to call you by number. The boarding confusion is comical,
I am waiting for someone to start a boycott allegiant airlines fan page on Facebook. I've given them many chances and they've truly failed me. Saving a few bucks flying this airline is simply not worth it. Also, they don't have a frequent flier program.