A technique is provided for the fabrication of multi-walled carbon nanotube (MWNT) and carbon nanofiber (CNF) film materials. The method includes mixing a relatively small amount of single-walled nanotubes (SWNTs) with larger amounts of MWNTs and CNFs, which enables one to produce highly flexible SWNT materials—advantageously without the need for bonding agents and at significantly lower costs compared to flexible SWNT materials. The method exploits SWNTs tendency to entangle together to form flexible films, using a small amount of SWNTs to wrap around and entangle the larger diameter MWNTs and CNFs together to form flexible films with highly beneficial mechanical, electrical, and thermal properties at a fraction of the cost of SWNT materials.