Flash sales typically only last several days and are meant to increase the extent of bookings made on certain dates of impending flights. Well-travelled people usually hold on until they get a special offer business class flights notice before they can make their international plans.They operate by working on low passenger days such as Tuesdays and Wednesdays when the airplanes have the least passengers. When you have a flexible schedule, these short term deals give you an excellent opportunity to experience lie-flat seating and fine dining.