Arrange one European trip (6)
I believe the answer is:
sortie
'trip' is the definition.
(I have seen 'short trip' mean 'sortie' so perhaps 'trip' could also mean 'sortie')
'arrange one european' is the wordplay.
'arrange' becomes 'sort' (I've seen this before).
'one' becomes 'i' (Roman numeral).
'european' becomes 'E' (abbreviation e.g. EU).
'sort'+'i'+'e'='SORTIE'
(Other definitions for sortie that I've seen before include "Offensive" , "Warplane's flight" , "Raid - short trip" , "Military aircraft's flight" , "Military foray" .)