Allegiant will probably do better in the next recession compared to its peers.

Unlike other airlines like WN or UA with massive orders of new planes to pay for on a monthly basis, Allegiant planes are old and paid for. The flight schedule can be reduced, and while revenue will also be reduced, expenses like fuel/salaries will be reduced by a corresponding amount. Meanwhile at other airlines they will be forced to fly new and expensive planes at a loss just to keep any kind of revenue coming in. This is just history repeating itself.