$99 Cheap United flights Phoenix (PHX) to Billings (BIL)

Finding cheap one-way United Airlines flights from PHX to BIL from $99 on Expedia is simple — just filter by "Price (lowest to highest)." Or check out our budget-friendly round-trip fares from $197 for your next break.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.

Look for cheap United Airlines flights from Sky Harbor Intl. Airport (PHX) to Logan Intl. Airport (BIL) one to three months ahead of your departure. Travelers who book domestic flights 34 to 86 days in advance can save 25% compared to those who book just 6 to 12 days ahead. Regardless of fare class and itinerary, the best day to book a domestic flight is usually Sunday and the most expensive day is typically Monday. Passengers who book on a Sunday can save 6% on average compared to those who book on a Monday.**Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.

Filter your results by "Morning" and "Early Morning" to find the earliest flights from PHX to BIL. Heading off early means you're 20% less likely to experience cancellations.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.

Journey from PHX to BIL with United Airlines and you can look forward to a range of perks starting with a rewarding loyalty program. When booking through Expedia as a United Mileage Plus and One Key™ member, you may also earn OneKeyCash™* to redeem on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.