Yes, the mayor was given a democratic mandate to try to boost the airport.... but the voters expect him to do so within reason. He's tried... he's spent a lot of money... and there's not a lot to show for it.
Projects which involve spending money need a regular review (e.g. every 6 months or year), to evaluate current progress against previous expectations, see what the future prospects are, and evaluate if the money is being spent effectively or whether the future money can be spent in different ways to achieve better results