What is the differences between a flight simulator and a real airplane

A simulator gives you the feel of the actual aircraft, but it won't be the real thing. For example, a simulator will contain all controls which an actual aircraft does, but it will have a display running some video and you have to move controls accordingly. If you crash in simulator you get one more chance to make a new start.

Real aircraft is a real thing. You crash, you are dead (Maybe along with some more guys and burning up millions of dollars).