Originally Posted by
neotope
If I go to a restaurant and get the early bird dinner which includes say an appetizer, main and dessert for a special price of $15.95. if I don't want the dessert they won't charge the higher fees even if say the main and appetizer separately might have been $19.95.
It isn't the same because in your example you aren't in a contract to sit in your seat and eat everything before leaving.
Off the top of my head, I can't think of a single restaurant that requires a customer to eat every piece of the entire meal to pay the menu price, other than my example. Nearly every restaurant will allow you to leisurely eat what you want in their establishment, and offer a box/bag for anything you want to take home.
The difference between that and buying and airline ticket is you are entering a contract to fly between specific points to get that price. Other than my example of the steakhouse, I can't think of a single restaurant that has any contracts with customers (other than the usual terms for sanitary or other reasons).