As with other airlines, United Airlines flight booking timing can greatly affect ticket prices. Your trip type (domestic or international), season, and reservation time all play a role. To find the best time to book cheap United Airlines flights, you may consider the following:
Domestic flights:
Booking domestic flights 1–4 months in advance is recommended. This range lets you take advantage of discounts while still having a good flight selection.
In off-peak seasons, which exclude summer, Christmas, and New Year's, booking one to three months in advance is ideal. Airlines often offer lower fares during these times.
Book summer vacations in January for the best deals. This month is one of the cheapest for flights.
International Flights:
International flights require more anticipation. Booking 4–6 months in advance is typical. This gives you time to find cheaper flights and more options.
Time of Day:
One theory is that the cheapest tickets are bought between 6 a.m. and noon. This may be due to lower demand or airlines releasing new fares at the start of the day.