What are all the airspaces for, the class A,B,C,D,E airspaces. What are the differences between them, except for the alts, and why do they have them? thanks.adam

Each class has different weather requirements, ATC, etc. Class B is a busy airport like Chicago O'Hare, while Class D would be a smaller towered airport. Obviously, Chicago will have different requirements than an airport that gets nothing but 172s.Check the AIM for more specific info:http://www.faa.gov/ATpubs/AIM/Chap3/aim0302.html

They don't list Class-G airspace :)It's not controlled by ATC though ;)