Taiwan is an island, no matter in island or between countries. It is very important for industry in Taiwan to use convenient and quick transportation mode. Especially, as the firm has to deliver cargo in faster transportation mode. The air freight has superiority. It becomes the indispensable transportation mode. Therefore, I want to use this model in the article to explain the realistic economic environment. Downstream firm purchases an input with time restricted, but it will cost a lot for transportation. One of the possible reasons is that the downstream firm wants to force upstream firm to lower its input price. And then I consider under this kind of industry, if upstream firm integrate forward vertically, it may promote the industrial profit.