Would that 40 million plus not be better spent on railways,roads and social services?
To be fair to the Mayor (!), he is delivering on his manifesto commitment. Clearly taking the airport back into public ownership has a cost, and the money spent on the airport is money that can't be spent on other public services, but that's what the electorate voted for.
His argument is that the airport will generate economic activity that will generate tax revenue in the region that will cover that cost.