How many letters does the top answer for “a simple type of jet engine; must be launched at high speed” have?

The most common answer is athodyd (7 letters).

Crossword clue: a simple type of jet engine; must be launched at high speed

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

athodyd 7 letters wn-def

a simple type of jet engine; must be launched at high speed

ramjet 6 letters wn-def

a simple type of jet engine; must be launched at high speed