For making decision Neeleman used six stages they are
Identifying and diagnosing the problem: The first step towards a decision making process is to define the problem. Obviously, there would be no need to make a decision without having a problem. So, the first thing one has to do is to state the underlying problem that has to be solved. Neeleman himself and with his staff spend quite time studying the customer problems and in convinces they faced during the flight. This helped him finding not only identifying and diagnosing the problem but also find out what customers wants and got fresh ideas.
Generating alternative solutions: The situation of making a decision arises because there are many alternatives