It was also Tony Hancock, although for a moment the name of the film escapes me. Hancock - dressed as a chicken - arrives breathless at a checkin in Paris.
The Kenneth Williams/Tony Hancock comments are about the Hancock's Half Hour episode called "The Test Pilot".
Hancock was the pilot and Kenneth Williams was a ground engineer who had been on the tailplane when Hancock took off. In flight he started knocking on the canopy asking to be let in.
The chicken bit is something else entirely.