Flying Graysons

The Flying Graysons were a team of trapeze performers at the Haly Circus. The are made up of John Grayson, his wife Mary Grayson, and their son Dick Grayson.

A mobster named Tony Zucco killed all but Dick Grayson when he sabotaged their circus act, causing the two of them to fall to their deaths, as there was no safety net below.

Reference
Super Friends (Season 1)
 * The Planet-Splitter