Yes, I noticed the same when writing about TT for my book, Nabokov at the Movies, particularly similar notions of death and falling, which is something Don talks about in his essay in the The Garland Companion. Kern's idea of death as “a gliding dream, a fluffy fall" prefigures the pleasure R. and his ghostly companions experience as they fall through layers of time, whereas this is the one prospect that instils abject terror in Hugh. There are also parallel notions of the ability to defy death through flight, i.e. the Superman episode and Hugh's dream about being on an aeroplane at the end of the novel. This connects back with Ivanov's "flight" at the end of Perfection and also notions of earthbound existence being similar to the dilemma of flightless birds, and the importance of dreams and the imagination in overcoming such corporeal constraints. Hermann Karlovich, for example, communicates this when he likens himself to the penguin who “flies only in its sleep”.