flybridge vs flying bridge

flybridge and flying bridge both are nouns.

Word	Noun	Adjective	Verb	Adverb
flybridge	Yes	No	No	No
flying bridge	Yes	No	No	No

As nouns, flybridge and flying bridge are synonyms defined as:

flybridge and flying bridge: the highest navigational bridge on a ship; a small (often open) deck above the pilot house

Other synonyms of flybridge include fly bridge, monkey bridge.

flybridge (noun)	flying bridge (noun)
the highest navigational bridge on a ship; a small (often open) deck above the pilot house	the highest navigational bridge on a ship; a small (often open) deck above the pilot house