There is a popular belief that if you book flights in advance, your air tickets will be cheaper. However, contrary to the popular belief, booking airline tickets late is often cheaper. As per the research, flight tickets are generally cheaper if booked three weeks before departure than tickets booked 6 months ahead. But, this is not necessary. The price of flights fluctuate daily or even hourly in various cases. Many times, it changes due to the increasing demand of a particular route by the passengers. So, sometimes flights get cheaper while traveling closer to the travel date and in some cases, it gets expensive.