Re: 49cc engines require driver's license
You are legal in AZ IF you were doing 20mph or less, without a drivers license/tag/insurance, if you are 16 or older.
Once you exceed 20mph, you are a motorcycle in AZ.
If you were observing the 20mph speed limit, print out the the appropriate AZ statutes and fight it in court. The legal section of this forum has plenty posts on AZ.
“You're only young once, but you can be immature as long as you like" -Unknown