The most common and most likely answer to this crossword clue is the 4 letter word EMUS
E
M
U
S
More clues leading to the result EMUS
- Birds around me, not them
- Flightless birds exhibited in innumerable museums
- Horse mushrooms, more than enough for birds
- Odd bits of pea mousse polished off? They’ll never take off
- Regularly reimburse Australian natives
- Perplex wingless birds
- Half of them going to America — they don’t fly
- Measure American or Australian runners
- Fox skinned birds
- Dance music featuring Australians?
Buddy explains!

The straight part
We know that "They’ll never take off" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they’ll never take off = emus.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does EMUS mean?
EMUS noun- A cassowary (genus Casuarius).
- A large flightless bird native to Australia, Dromaius novaehollandiae.
- A person or thing that emulates.
- A piece of software or hardware that simulates another system.