For most major airlines, you can buy tickets approximately in advance. While this is the standard window for full-service carriers, budget airlines often use a shorter or more irregular schedule. Typical Booking Windows by Airline Type

Booking as early as possible rarely yields the lowest price. Experts often refer to a "Goldilocks Window"—not too early and not too late—to find the best deals. Destination Recommended Booking Window Sweet Spot 1–3 months in advance ~44 days out International 2–8 months in advance ~129 days out (for Europe) Peak Holidays 3–10 months in advance As early as possible Best Day And Time To Buy Plane Tickets - Forbes

Many major international airlines, including British Airways and Lufthansa, release flights up to 355–362 days out.

Airlines like American Airlines , Delta , and United typically open bookings 330–331 days before departure.

Most airlines operate on a rolling schedule where new dates are added daily.

Airlines such as Southwest, Frontier, and Spirit do not have a fixed 11-month window. For example, Southwest Airlines typically releases seats in blocks about 8 to 10 months ahead. European budget carriers like Ryanair may only open bookings 6 to 9 months in advance. The "Goldilocks Window" for Best Prices