Designation of fighter plane brought in to fly until now (2,3)
I believe the answer is:
so far
'until now' is the definition.
(both can mean up to the current point)
'designation of fighter plane brought in to fly' is the wordplay.
'designation of fighter plane' becomes 'F' (abbreviation used in names of aircraft).
'brought in to' indicates putting letters inside.
'fly' becomes 'soar' (soaring is a kind of flying).
'f' going within 'soar' is 'SO FAR'.
(Other definitions for so far that I've seen before include "till now" , "To this point" , "Up until the present moment" , "to a certain degree" .)