Independent producer Ken Snyder (Roger Ramjet) sold a pair of series to ABC in 1969. He'd obtained a license from Mattel to do a series based on their Hot Wheels line of toy cars, but his other series, Skyhawks was loosely based on the 50's live-action series, Sky King.
Skyhawks, unfortunately, lasted just one season due to poor ratings, while Hot Wheels was forced off the air due to FCC concerns about it being a glorified infomercial for Mattel. Michael Rye, who was the original cartoon voice of The Lone Ranger, but is better known to toon fans for his years of work on Super Friends, narrates the opening sequence, uploaded by Muttley16 to YouTube:
In case you wonder, the theme song was composed and performed by Mike Curb & the Curbstones. Too bad this show was lost in the mists of time, as it could pick up a new audience today if someone had the stones to acquire it.