An airplane hauling a banner insulting New York City Mayor Bill de Blasio has been spotted flying above New York City.

The banner Friday read: "De Blasio, our backs have turned to you."

Some New York Police Department officers and police union leaders last week turned their backs to the mayor after two officers were fatally shot.

Story continues below advertisement

The deaths followed protests around the country over the deaths of black men at the hands of white officers. New York police unions have blamed de Blasio for allowing protests they say foster an anti-police sentiment.

Former officer-turned-activist John Cardillo said retired and current officers paid to have the banner flown.

A de Blasio spokesman called the banner divisive.