A dictionary of Confusable Phrases: More Than 10,000 Idioms and Collocations

fly the flag • keep the flag flying
fly the flag —
1
. (of a ship) be registered to a particular country
and sail under its flag: Swearing an oath to revenge … he
resolved to plunder any ship flying the flag of Spain. 2. (also:
show the flag ) represent one’s country, etc. (by attending an
event): Without their assistance, there would have been far
fewer UK delegates at the meeting to “fly the flag.”
Note: 
The expression does not correlate in meaning with the
phrase fly the wrong flag—(corporate culture) behave or act in
a manner deemed inappropriate: I was not aware that wearing
open-toed shoes to work was tantamount to flying the wrong
flag.
keep the flag flying —
1
. refuse to succumb; show continued
commitment: It’s been quite a challenge for the few remaining
teachers to keep the flag flying. 2. = fly the flag 2: The British
delegation led by John Davis kept the flag flying! All in all it
was like meeting old friends…
flyboy • flyman
flyboy —(U.S. sl.) a member of an air force, especially a pilot:
And, of course the infantry objected to the glorification of the
flyboys.
flyman —
1
. (Theater) a man stationed in the “flies” to work
the ropes, etc.: The flyman may be said to carry some of the
destiny of the performance in the hollow of his hand. 2. a
person who drives a “fly”— a light vehicle as a cab or hansom:
When the proof of that journey was obtained from the flyman,
the evidence would be complete.
flyfish • flying fish
flyfish —
1
. (used as a verb) angle with a hook baited with
(artificial) flies: There are many videos and classes around to
teach you how to flyfish in very little time. 2. (used as a noun)
a California fish (Sebastichthys rhodochloris), having brilliant
colors: We went on fishing and I was the one with the best
fish luck, I caught a flyfish on the hook.
flying fish —fishes, chiefly of tropical seas, capable of leaving
the water and moving some distance through the air: Every
now and then a flying fish would spark out from the unruffled
bosom of the heaving water.