Jerry plans to meet a supermodel girlfriend at an airport lounge (the “Diplomat’s Club” of the title) after returning from a quick air roundtrip to a “gig” in Ithaca, but his assistant makes the trip a nightmare. Elaine is planning to tell Mr. Pitt she is quitting, but reconsiders when he tells her that she’s going to be in his will. George tries to prove to his boss, Morgan, that he is not a racist, as Morgan has been offended when George tells him that he looks like Sugar Ray Leonard (“I suppose we all look alike to you”). Mr. Pitt goes to the pharmacy and mistakes Jerry for a pharmacist, as he is re-stocking a display that Kramer had knocked over. Jerry then proceeds to give Mr. Pitt some medications. Kramer, loitering in the Diplomat’s Club waiting for Jerry to return from Ithaca, meets a rich Texan, Earl Haffler, with whom he starts making bets on aircraft arrival times. In Ithaca, Jerry’s assistant invites the pilot to his comedy routine, then warns Jerry not to be nervous about it, which makes Jerry extremely nervous, causing him to “bomb”, leading the officious assistant to harangue the pilot. When Jerry tries to fly back to New York, the same pilot, flying the return flight, throws him off the plane, delaying the flight. The ditzy assistant rents a car and tries to drive Jerry back, but gets lost and drives into a swimming pool, which leads to TV news coverage. Meanwhile, George is so desperate to find an African-American to pose as his friend, that he asks the African-American man whose house he invaded in “The Couch”. When he refuses, George tries to befriend Karl, the exterminator who fumigated Jerry’s apartment for fleas in “The Doodle”.
After Mr. Pitt nearly dies due to taking a cold medication which interacted badly with his heart medication, he suspects Elaine is trying to kill him after he sees Jerry on the news, and recognizes him as the “pharmacist” who gave him the medications. His attorney remembers that Jerry called for Elaine, earlier in the show, and assumes that they are in a plot to kill him, now that she is in his will, leading Pitt to fire Elaine. Kramer loses his betting winnings after Elaine drops by the Club looking for the model and informs him that Jerry caused a disturbance on the flight from Ithaca (Kramer’s big final bet), delaying the flight by an hour. When the Texan hears this, he thinks that the betting was rigged, and tears up his check to Kramer. George & Karl go to a posh restaurant where Morgan is eating. George asks Karl to pose as his friend. When Karl introduces himself as the exterminator, George covers up with a phony story. The plot backfires when Karl admits to Morgan that he is actually an exterminator. Morgan then tells George that he has sunk to a new low and leaves in disgust. When George calls for the check, the black waiter sees Morgan leave and says “Sugar Ray Leonard can eat here on the house”, which proves George was right and sends him sprinting after Morgan. In the final scene, Jerry and the model meet at last in the Club, just before her plane leaves, and start to “make out”, but the sudden reappearance of the pilot, as his plane pulls up next to the club window, again unnerves Jerry.