SÃ£o Paulo: the worldâs biggest helicopter fleet. Above the rooftops of a megacity: The helicopteromania of SÃ£o Paulo. SÃ£o Paulo, during the afternoon peak hour, a sheer endless queue of vehicles stretch along the Avenida RebouÃ§as in SÃ£o Pauloâs upper-class neighbourhood Pinheiros. The exasperated drivers are literally stuck in the streets.