Many viewers were upset over the Aer Lingus sketch with its Irish stereotyping. Aer Lingus themselves were upset over the sketch and wrote negative things about it on Twitter.
John McEnroe saying "Are you kidding me?" is probably a gag on him always saying "You cannot be serious" when he was upset on line calls.
The nonsense song that Saoirse Ronan performs explaining how to pronounce her first name is a take-off of "Liza With a Z," the comic tune Kander and Ebb wrote for Liza Minnelli's eponymous 1972 TV special - Liza with a Z (1972).
Greta Gerwig: The director of Lady Bird (2017) (which starred Saoirse Ronan and was in theaters when this episode aired) appears as the boss in "The Race."