With Allegiant, you're not getting just a seat on a plane - you're getting the whole package. Book now to save on high-quality seats and in-flight entertainment, from an industry leader with over 20 years of experience. Allegiant Airlines is an American low-cost airline that operates in the U.S. and Canada. It carries more than 12 million passengers per year to more than 100 destinations in North America, Central America, the Caribbean, and South America.