How many letters does the top answer for “director of rush hour” have?

The most common answer is chan (4 letters).

Crossword clue: director of rush hour

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

chan 4 letters wd-fact-v3

director of the children's hour 50% similar → wyler

director of the desperate hours 50% similar → wyler