When do airlines lower their prices?

Airlines don't lower prices on a specific date: revenue management systems do, splitting each flight into fare classes and opening or closing the cheapest ones depending on how bookings are tracking against forecasts. If a flight is filling more slowly than expected, the system reopens low fares; if it fills faster, it closes them. That's why the same seat can cost twice as much from one day to the next, and why dated promotions (January sales, Black Friday) are the only genuinely scheduled price drop.

Analyses from search engines and travel agencies agree on some general patterns. For short and medium haul, the cheapest window usually falls between one and three months before departure; for long haul, between two and six. From about two or three weeks out the curve almost always rises, because late bookers tend to be business travelers less sensitive to price. The day of the week matters too: Tuesday, Wednesday and Saturday departures tend to be cheaper than Friday and Sunday ones, and early-morning or late-night flights more than mid-morning ones. By season, the second half of January, February, and the stretch from mid-September to November hold the lowest fares of the year in the northern hemisphere.

Buying on a Tuesday afternoon, clearing cookies, or waiting until the last minute are beliefs with no backing: price depends on expected occupancy, not on the browser, and the seats left at the end are sold at a premium. What does help is comparing nearby airports, setting up price alerts, and being willing to shift travel dates by a day or two, which is where the biggest differences show up.