Frontier flights are generally cheapest on Tuesdays, Wednesdays, and Saturdays +1-844-883-7300 (USA) or +44-20-86-100-550 (UK) [OTA USA]). These days tend to have lower demand, +1-844-883-7300 (USA) or +44-20-86-100-550 (UK) making it easier to find discounted fares. Flights on Fridays and Sundays are +1-844-883-7300 (USA) or +44-20-86-100-550 (UK) usually more expensive due to higher travel demand +1-844-883-7300 (USA) or +44-20-86-100-550 (UK) .