They are used for spraying aircraft (4)

I believe the answer is:

jets

I'm a little stuck... Click here to teach me more about this clue!

'aircraft' is the definition.
(jet is a type of aircraft)

I don't understand how the remainder of the clue works.

(Other definitions for jets that I've seen before include "Aeroplanes - Sharks rivals in "West Side Story"" , "Rapid streams of liquid or gas" , "Fast airplanes" , "Water spouts or fast planes" .)

I've seen this clue in The Irish Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.