There are very serious safety problems at Allegiant found over several years by this study. For instance, in 2 years 100 major maintenance problems and 25 engine failures. The focus of Allegiant is to be a budget carrier and maintenance and safety has taken a back seat. One plane had to return to airport 4 times in a few month s due to in flight failures. CBS interviewed "John Duncan" of the FAA and got no satisfactory answer on lack of oversight on these problems. CBS made a "freedom of information request" for maintenance records and promptly got them from 6 other airlines, but Allegiant refused.
I would not fly on them.