The most common and most likely answer to this crossword clue is the 4 letter word JETS
I've seen this crossword clue in The Daily Telegraph
J
E
T
S
Buddy explains!
The straight part
We know that "aircraft" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case aircraft = jets.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 JETS mean?
JETS noun- A collimated stream, spurt or flow of liquid or gas from a pressurized container, an engine, etc.
- A spout or nozzle for creating a jet of fluid.
- A type of airplane using jet engines rather than propellers.
- An engine that propels a vehicle using a stream of fluid as propulsion.
- A part of a carburetor that controls the amount of fuel mixed with the air.
- A narrow cone of hadrons and other particles produced by the hadronization of a quark or gluon.
- Drift; scope; range, as of an argument.
- The sprue of a type, which is broken from it when the type is cold.
- To spray out of a container.
- To spray with liquid from a container.
- To travel on a jet aircraft or otherwise by jet propulsion
- To move (running, walking etc.) rapidly around
- To shoot forward or out; to project; to jut out.
- To strut; to walk with a lofty or haughty gait; to be insolent; to obtrude.
- To jerk; to jolt; to be shaken.
- To adjust the fuel to air ratio of a carburetor; to install or adjust a carburetor jet
- To leave.
- A hard, black form of coal, sometimes used in jewellery.
- (color) The colour of jet coal, deep grey.