Aviation industry information and air travel tips, guide and resources on international air travel, airline companies, weather, air fares, tickets and reservations. Most things that are bought and sold have a high incremental cost and a low fixed cost, most of the selling price for a car, or a can of soft drink, is represented by the incremental cost of making and distributing the extra car or the extra can of soft drink. Small part of the cost goes to fixed or overhead costs. But in the airline industry, the incremental costs of accepting one extra passenger onto a plane are very low. In the process, Europeans have changed not only their travel choices but the way they behave. Be flexible in scheduling your flight. Tuesdays, Wednesdays and Saturdays are typically the cheapest days to fly late night flights, very early morning flights.