Air France and KLM have introduced a “Time to Think” feature when booking flights online at airfrance.com and klm.com. For a fee, you can hold a fare at a guaranteed price from 24 hours up to 14 days. To confirm your booking, go to the “Manage your reservation” area of the website. If you don’t confirm, the booking will automatically lapse. The cost is 10 or 15 euros based on your cabin class and destination.