The arrival of a commercial airway (6)

I believe the answer is:

advent

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'the arrival of' is the definition.
(I've seen this before)

'a commercial airway' is the wordplay.
'a commercial' becomes 'ad' (abbreviation for advertisement).
'airway' becomes 'vent' (I can't explain this - if you can you should believe this answer much more).
'ad'+'vent'='ADVENT'

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(Other definitions for advent that I've seen before include "Arrival (with calendar?)" , "when the Church year begins" , "approach" , "sort of calendar" , "Coming - occasion in Church calendar" .)

I've seen this clue in The Globe and Mail.

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