In 1978, the folks at NBC were seeing the success rival CBS was having in the Saturday morning ratings with The Bugs Bunny/Road Runner Show and jumped on the bandwagon by picking up their own package of Warner Bros. shorts to play on Saturdays. With CBS holding the network rights to most Bugs Bunny, Road Runner, and Tweety and Sylvester cartoon shorts, NBC had little option but to air a series starring Daffy, the only major Warner Brothers cartoon character with a sizeable number of Warner-owned cartoons available outside of the rights held by CBS. Though NBC obtained some pre-1960 classics, by and large the cartoons that it purchased the rights to air were post-1960, including nearly all of the team-ups of Daffy with Speedy Gonzales. Each half-hour episode of The Daffy Duck Show contained 4 cartoon shorts. The show first aired on November 4, 1978 and ran on NBC until 1981. After NBC dropped the Daffy package, CBS quickly snatched up those cartoons and assembled a short-lived half-hour entitled The Sylvester and Tweety/Daffy and Speedy Show before eventually merging all the cartoons into their Bugs Bunny/Road Runner Show in 1982.
Here is the rarely seen opening to NBC's Daffy Duck Show: