According to a study carried out by travel website Kayak in the US the best time to book a flight is 21 days before departure.
According to a study of millions of flights booked by Kayak users over a six-month period, the average fare for a domestic flight in the US is $370; the fare drops to its lowest level, $342, when booked 21 days before departure date.
However, when booking an international fare, the best rate can be booked 34 days before departure, when the average fare drops to $997 from $1,016.
The study also shows that for short domestic trips in the US passengers can save up to 16 percent by departing on a Saturday and coming back on a Monday.
For trips longer than a week, passengers can save up to 10 percent by traveling on a Tuesday and returning on a Wednesday.