Cities have the option to ban take off and landing within their jurisdiction, similar to national parks, but they cannot control the airspace. Only the FAA has the authority control the airspace. That information is available through the FAA or other organizations like AirMap.com
If the city is banning taking off and landing anywhere in the city, that's usually only city owned property, like parks, schools, streets, etc. Usually private property is exempt. So you can take off at your house, on your property, and fly where you want. Likewise, if you are doing a commercial job, you can get permission from the property owner to take off and land from their property, and fly where you want, as long as you are following FAA Part 107 guidelines. As for recreational flyers, you may be screwed if you want to fly at parks, rivers, or other city owned property.
I guess I won't be visiting Wyandotte, MI anytime soon.
One way to combat this is to get help from your local newspaper. If you can befriend a reporter to write an article on this subject, letting the residents know what's happened, letting everyone know they
should not be buying toy drones for their kids, maybe some pressure from the public can reverse this stupid decision.
Usually these ordinances are prompted by rich people that don't want drones flying over their homes. They can have lots of influence on city councils, as money speaks. The only way to fight this trend is through numbers of people in the city that vote for the city council. If the council feels they will lose their job from public pressures, they tend to reverse their voting representation of the public, if they want to keep their job. On drone issues, that may be a difficult pitch to the residents.