It's worth noting that the "Mayor" is largely a ceremonial position in Broward County. It's a position voted on solely by the members of the Broward Commissioners. (The Commissioners are the people that are elected by the voters.)
I'm fairly certain the "Mayor" doesn't have the authority to make that decision on his own. He'd need the backing of other members of the Broward Commissioners. Hopefully, the majority of the Commissioners will recognize the fact that this action would be subject to lawsuits from the airlines (once the aircraft is officially re-certified).