Airlines are backing the Commerce Commission's decision to stop short of a formal inquiry into airport regulation. 

It's instead looking at changing how much information airports should provide airlines about major upgrades. 

This follows Air New Zealand writing to the regulator, raising that the costs it was facing from airports were growing out of control. 

Board of Airline Representatives Executive Director Cath O'Brien says a formal inquiry wasn't worth it.  

She told Mike Hosking the process is complicated, expensive, and not fit for purpose, as if they ran it, they’d have to apply the findings to all airports, not just one.  

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