The title refers to Lester Flatt and Earl Scruggs from the Grand Ole Opry who were the guest stars and who played the series theme song "The Ballad of Jed Clampett", which reached #42 on the record charts during the series' debut season of 1962.
In the first five minutes of this episode there are three scenes involving the characters in vehicles: 1. Jed and Jethro in the truck (with a helicopter blade attached). 2. Jane Hathaway, Lester Flatt, Gladys Flatt, and Earl Scruggs in Miss Hathaway's convertible. 3) Mr Drysdale and his chauffeur in the limousine.