You can purchase Allegiant Air tickets in advance by booking online at AllegiantAir.com, calling the airline's customer call center or purchasing tickets at the airport ticket counter. As of April 2015, Allegiant adds convenience fees for customers who make reservations online or over the phone.
Allegiant Air's customer call center can be reached at (702) 505-8888. As of April 2015, the call center is open from 4 a.m. to 11 p.m. Pacific Daylight Time, seven days a week.
When creating an online reservation, you can research your flight options by using the airline's Book a Trip tool. Allegiant does not fly every day of the week, but the tool shows you the closest travel dates if the dates you're looking for are not available.
Once you select the number of passengers and your desired flight, you can add optional features before checking out. As of April 2015, Allegiant Air charges additional fees for checked bags, carry-on bags, priority boarding and seat assignments.
You can avoid paying convenience fees by booking in person at an airport ticket counter. However, Allegiant Air ticket counter hours are limited and vary by airport, so it's usually a good idea to call the airport before visiting.