Aluminium lined sleeve frayed at low altitude (3-5)

'low altitude' is the definition.
The answer and definition can be both human attributes as well as being singular nouns.
Perhaps they are linked in a way I don't understand?

'aluminium lined sleeve frayed' is the wordplay.
I cannot really see how this works, but
'aluminium' could be 'al' (Al is the chemical symbol for aluminium) and 'al' is found within the answer.
an anagram of 'sleeve' is 'seevel' which is present in the remaining letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).

'at' acts as a link.

Can you help me to learn more?