Europe: Aim for the longer end of that window, ideally ahead.

For the best balance of price and availability, aim for these general timeframes based on your destination: Book 1 to 3 months in advance.

Mexico/Caribbean: A shorter window of is often sufficient. When to Book Even Earlier

If your plans aren't flexible, the "Goldilocks Window" might be too risky. You should book as soon as schedules open (typically ) for: How Far in Advance Should You Really Book a Flight? - Going