Herein, we demonstrate a new approach towards the construction of supercapacitors consisting of carbon nanotubes (CNTs) and conducting polymers (ECPs) with high specific power, high specific energy, and stable cycling performance through a 3D design of a thin film of polyaniline (PANI) on an aligned small carbon nanotube (ACNT) array on household Al foils. The thin-film strategy is used to fully exploit the specific capacitance of PANI, and obtain regular pores, strong interaction between PANI and CNTs, and reduced electrical resistance for the electrodes. A facile process is developed to fabricate a highly flexible supercapacitor using this binder-free composite on household Al foil as the current collector. It exhibits high specific energy of 18.9 Wh kg−1, high maximum specific power of 11.3 kW kg−1 of the active material in an aqueous electrolyte at 1.0 A g−1, and excellent rate performance and cycling stability. A high specific energy of 72.4 Wh kg−1, a high maximum specific power of 24.9 kW kg−1, and a good cycling performance of the active material are obtained in an organic electrolyte.