Advance purchase

The number of days before departure a fare requires you to buy — the AP in fare-speak, commonly 21, 14 or 7 days on discounted business fares. Advance purchase is why premium prices climb as departure approaches: the cheap buckets close by rule, not by seat count. The flip side matters too: negotiated contracts often carry shorter AP requirements than published fares, which is why a specialist quote frequently beats the engines hardest inside two weeks of departure.