All a Bir-r-r-rd (1950)

Continuity mistake: When the conductor swats Sylvester's paw after he attempted to grab Tweety, you can see the door to Sylvester's carrier is open, but when the conductor takes Tweety's cage, we cut to Sylvester and the door to his carrier is now closed.

Trivia: When Sylvester slides down into the bulldog, who punches him and sends Sylvester into the wall, look in the background and you can see a chest with a label saying "From Friz Freleng, Pratt Falls." Friz Freleng is the director of this cartoon, whereas "Pratt Falls" is a reference to the Warner Brothers layout artist Hawley Pratt.