Randy tells Cynthia that he didn't attend her farewell cocktail party because he didn't have any Flit, and wouldn't go without it. Flit was a brand of insecticide invented in 1923 and used mainly for flies and mosquitoes. Randy is implying that Cynthia's friends are a bunch of bar flies.
For the 2021 restored print shown on Turner Classic Movies, there is a missing part of the scene in the English pub. The audio track was discovered intact, so the restorers used production stills to fill in the gap.
The $60,000 Cynthia says she earns would be equivalent to about $1.35M in 2022.