When's the best time to buy? Travel experts have long said Tuesday is when sales are most often in place, which is true. An analysis of domestic fares shows that Wednesday also has good—and occasionally better—ticket prices.

Though prices fluctuate frequently and the ups and downs of airline prices can frustrate and anger consumers, airline pricing actually does follow a cycle during the week. Many sales, in which some seats are discounted by 15% to 25% typically, are launched Monday night. That was true again this week when AirTran Airways launched a sale to all its destinations. Competitors typically match the lower prices Tuesday morning. By Thursday or Friday, many sales have already expired.