When you add up taxes, baggage fees, seat selection fees, and all of the other costs that come with booking a flight, the price can rise quickly. Luckily, there are ways to keep the cost down. Follow these tips the next time you book a flight to lessen the blow on your wallet. When it comes to booking a flight, timing is everything. Typically, the best time to book a domestic flight is 6-8 weeks before traveling, and 2-3 months before international travel.