Depends on where you are- and you did not tell us where. Sorry.
it depends how old you are and if you are playing airsoft for a job instead of a hobby
Federal law to purchase is 18 for long guns and 21 for handguns.
yes, you can and need a license to own an airsoft gun in nyc.
I don't think you have to have a license to work on guns, but I'm not sure about that. To manufacture guns, you have to have a manufacturers license. Check with the BATF for more information.
a license
It depends on several factors; Where you are located and exactly what you mean by "gun license." Do you mean a license to carry a gun? A license to purchase a gun? A license to build guns?
No set number. But if you are "engaging in the business " of buying and selling guns, you need a dealer's license.
No, but a toy license would be acceptable.
What guns?
Yes you need a valid state license to purchase any guns.
Depends on where you are, and how recently.
If you have a license as a gun dealer, along with business license and meet zoning laws.