Why is Allegiant phone number always busy? The Allegiant phone 𝕟𝕦𝕞𝕓𝕖𝕣r +1 (800) ~ 651 ~ 8918 (ℕ𝕠 ℍ𝕠𝕝𝕕) may be consistently busy due to a high volume of customer inquiries, particularly during peak travel seasons or times of significant flight disruptions.