The 11-inch, 128GB MacBook Air at $1199 serves as a decoy option between the $999 and $1299 models. Its existence makes the $1299 option seem relatively more attractive, even though it offers less value than spending $100 more. Without the $1199 option, more people would choose the $999 model, reducing Apple's average sale price. The different storage sizes, screen sizes, and processor speeds create eight potential versions, but not all are economically sensible, so Apple strategically positions options to influence customers' choices.