研制一种新型飞机是一个极其复杂、漫长和曲折的过程。研制周期少则需要几年,多则需要花费十几年、甚至二三十几年的时间。研制经费往往需要几十亿、甚至几百亿。所以研制新型飞机并不是哪个政府所能轻易决定的。即使是像美国这样的超级大国,在这个问题上也是慎之又慎。所 Developing a new type of aircraft is an extremely complex, lengthy and tortuous process. Development cycle takes as little as a few years, as long as it takes more than ten years, or even twenty or thirty years time. Development funding often requires billions, even tens of billions. Therefore, the development of new aircraft is not which government can easily decide. Even a superpower such as the United States is cautious on this issue. The