Timing matters when booking international flights. Research consistently shows that the sweet spot for purchasing international airfare is between 2 and 8 months before departure. Book too early and airlines have not yet released their competitive pricing. Book too late and you are stuck with whatever is left.
For transatlantic flights to Europe, aim to book about 2 to 3 months in advance for summer travel and 1 to 2 months ahead for fall and winter. Asia-Pacific routes tend to require more lead time. Booking 3 to 5 months out for flights to Japan, Thailand, or Australia usually yields the best prices.
Shoulder seasons offer the best combination of low fares and good weather. For Europe, that means April through mid-June and September through October. For Southeast Asia, November through February avoids monsoon season while keeping prices reasonable.
Keep in mind that holiday periods around Christmas, New Year, Chinese New Year, and spring break always command premium pricing regardless of when you book. If you must travel during these windows, book as early as possible and consider alternative routing through less obvious hubs.