1 Answer

APEX "stands for Advance Purchase Excursion. The simplest way to explain this is that the airlines have varying ranges of their lowest ticket prices and rules based on whether you're doing your booking 7 days out versus 14 or 21 or longer. Once upon a time, there were promotional fares that were much lower if you were flying on weekdays versus weekends, staying for a specified minimum number of days, or whether your stay included a Saturday night. People tended to plan their vacations and business travel around those conditions because they knew they could save money rather than simply picking their dates first and automatically accepting whatever the cost happened to be."