Line in solid design of aeronautical engineering triumph (8)
I believe the answer is:
concorde
'design of aeronautical engineering triumph' is the definition.
The definition suggests a singular noun which matches the answer.
'line in solid' is the wordplay.
'line' becomes 'cord' (cord is a kind of line).
'in' indicates putting letters inside.
'solid' becomes 'cone' (3D shape).
'cord' placed within 'cone' is 'CONCORDE'.
Can you help me to learn more?
(Other definitions for concorde that I've seen before include "Name of supersonic airliner" , "Supersonic airliner recently discontinued" , "Supersonic aircraft no longer in service" , "Airliner retired in 2003" .)