"Dear Liam, I failed" - sent by pilot (9)
I believe the answer is:
airmailed
'sent by pilot' is the definition.
'airmailed' can be an answer for 'sent' (airmailing is a kind of sending). I am unsure of the 'by pilot' bit.
'dear liam i failed' is the wordplay.
'failed' indicates anagramming the letters.
'dear'+'liam'+'i'='dearliami'
'dearliami' is an anagram of 'AIRMAILED'.
Can you help me to learn more?
(Other definitions for airmailed that I've seen before include "sent via Dakota?" , "Sent by plane" .)