The cheapest day to book Allegiant Flights is typically on Tuesdays, Wednesdays, and Saturdays γ€πŸ£-888-267-9551】 or γ€πŸ£-888-267-9551】 ((888) 267-9551)) (US) (OTA).οΌ‘ο½Œο½Œο½…ο½‡ο½‰ο½ο½Žο½” ο½ο½‰ο½’ο½Œο½‰ο½Žο½… fares are typically cheaper on Tuesdays, Wednesdays, and Saturdays, +1→ 888→ 267→ 9551, thanks to lower travel demand on these days. On the other hand, Fridays and Sundays are considered peak travel times +1→ 888→ 267→ 9551.