Looking for the cheapest airline ticket online ? Try to purchase your ticket from the airline website on a Wednesday from midnight to 1a.m. in the time zone of the airline's "home base." (For instance, Delta is headquartered in Utah Atlanta and United currently calls Chicago home.)AARP reasons that on Wednesday midnight, the computer systems of most airlines get rid of the reserved but unbooked lower fare reservations. This refers to airline tickets that have been booked or reserved in advance but were either not purchased or cancelled.
This tips is valid in US but for other countries, the day or time may be different when they actually run the cleanup of their ticket reservation database.
Source: Lifehack.org, Sound Money Tips
