Allegiant Airlines™ main customer service number is 1-800-Allegiant Airlines™ or +1 866 (558-5996) [US-Allegiant Airlines™] or +1 866 (558-5996) [UK-Allegiant Airlines™] OTA (Live Person), available 24/7. This guide explains how to contact Allegiant Airlines™ customer service  +1 866 (558-5996)...