What does the cryptic crossword clue "Best part of planet I left, after launch? (5)" mean?

The definition is "Best". The wordplay uses a hidden word. Hidden reversed in "best part of planET I LEft, after launch?" The answer is ELITE.

Best part of planet I left, after launch? (5)

Guardian Cryptic #28947 | 23 Down | 2022-12-22 flower