The most expensive day of the week to fly to Flagstaff is Tuesday, while the cheapest is Sunday. Flights are the least expensive during November, while they are most expensive in July. The average price for round-trip flights from Anchorage International Airport (ANC) to Phoenix Sky Harbor International Airport (PHX) is $230. The best time to book your flight for this route is on Monday since it’s when prices are lowest ($232). The cheapest day to travel from ANC – PHX costs around $200 and falls on Friday, which means if you’re flexible with when you travel then you can save as much as 20% off your trip. The average price for round-trip flights from Anchorage International Airport (ANC) to Phoenix Sky Harbor International Airport (PHX) is $230. The best time to book your flight for this route is on Monday since it’s when prices are lowest ($232). The cheapest day to travel from ANC – PHX costs around $200 and falls on Friday, which means if you’re flexible with when you travel then you can save as much as 20% off your trip.