There's no magic moment that always gives the lowest price — but timing and flexibility genuinely move the needle. Here's what tends to work.
As a rough guide (these are tendencies, not guarantees — fares are dynamic): for short-haul and domestic trips, the sweet spot is often around one to three months ahead; for long-haul and international, around two to six months.
Leaving it to the last couple of weeks usually costs more, while booking extremely early rarely beats the sweet spot. Watch the trend rather than chasing a single perfect day.
When you fly matters more than when you book. Flying midweek (Tuesday or Wednesday) and at unpopular times — very early or late — is often cheaper than weekends and peak hours.
The old advice to "book on a Tuesday" is mostly a myth. The day you click buy makes far less difference than your travel dates and how flexible you can be.
Holidays, school breaks and big events push prices up. Shifting your trip by even a few days around those periods can save a surprising amount.