Taking flight from here to America, about to tackle a grid-filling problem (6)
I believe the answer is:
sudoku
'a grid-filling problem' is the definition.
(puzzle in which numbers are filled into a grid)
'taking flight from here to america about to tackle' is the wordplay.
'taking flight from' says the letters should be written backwards (in a down clue, letters go up).
'here' becomes 'UK' (the clue is from a British publication).
'to america' becomes 'US' (abbreviation for the United States).
'about' means one lot of letters goes inside another.
'to tackle' becomes 'do' (do can mean to take on or tackle).
'uk'+'us'='ukus'
'ukus' back-to-front is 'suku'.
'suku' enclosing 'do' is 'SUDOKU'.
(Other definitions for sudoku that I've seen before include "(Usually) nine-by-nine numbers puzzle" , "Boxing contest" , "Numeric puzzle" , "Popular number puzzle" , "Japanese number puzzle" .)