In this season, Larry plays Max Bialystock in The Producers on Broadway and is visited by his cousin Andy when in New York. Richard Kind who plays Cousin Andy actually played Max Bialystock on Broadway in 2005.
The St James theater is also where Birdman was filmed. When Larry visits Cady Huffman's dressing room, the passageway is one that features prominently in the 2014 film.
The short story element of Jeff just sitting and staring/doing nothing during the flight mirrors the exact same storyline in The Butter Shave (1997) when Elaine flies home from Norway with David Puddy. Just like Larry, she gets into a whole ordeal about it with David.