When the senator tries to drown out the Piper's flute by turning on the radio in his office, the music being played is Dan's jazz trumpet from the earlier episode Giants and All That Jazz (1969).
When the piper talks about all the planets he has jobs on he mentions Alpha Centauri. Of course, this was the destination the Jupiter 2 was heading for in Lost in Space (1965), which Jonathan Harris played the nefarious Dr. Smith.
The title and plot refers to the Pied Piper of Hamelin, a legend about the abduction of many children from the town of Hamelin, Germany and used in stories written by the Brothers Grimm and Robert Browning. The title also refers to the expression "Pay the Piper," where one must bear the consequences of an action or activity that one has enjoyed.
Fitzhugh's Speech, adapted from
"The Pied Piper of Hamelin"
By Robert Browning
"Into the street the Piper stept, Smiling [just] a little smile, ...And ere three shrill notes the pipe[r] uttered, You heard as if an army muttered; And the muttering [became] ... a mighty rumbling; And out of the houses the rats came tumbling. ...[And] followed the piper for their lives..."
"Into the street the Piper stept, Smiling [just] a little smile, ...And ere three shrill notes the pipe[r] uttered, You heard as if an army muttered; And the muttering [became] ... a mighty rumbling; And out of the houses the rats came tumbling. ...[And] followed the piper for their lives..."
While shooting this, his only guest appearance on an Irwin Allen series other than Lost in Space (1965), Jonathan Harris confronted Kurt Kasznar to try to get him to admit that Allen had pressured him to "steal" the Dr. Smith character in creating his own variation on the comic cowardly villain with a heart of gold, Alexander Fitzhugh, with Kasznar's stark denial being unconvincing to Harris for the remainder of his life.