AirAsia is proud to be the best low-cost airline on the planet. Headquartered in Kuala Lumpur, it offers domestic and international flights to over one hundred destinations across twenty two countries, and counting. Believe it or not, AirAsia operates with a unit cost of less than a quarter dollar per available seat kilometer. That’s not even the best part. It allows travelers to save even more by giving out an AirAsia discount every time they book online using coupons.