Trust the flight will have a safe conclusion (4)
I believe the answer is:
hope
'trust' is the definition.
(synonyms)
'flight will have a safe conclusion' is the wordplay.
'flight' becomes 'hop' (I can't justify this - if you can you should believe this answer much more).
'will have' is a charade indicator (letters next to each other).
'conclusion' suggests the final letters.
The final letter of 'safe' is 'e'.
'hop'+'e'='HOPE'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for hope that I've seen before include "combination of expectation and desire" , "Confident expectation" , "Bob --, US comedian" , "Bob --, US comic" , "Companion to faith and charity" .)