LT42 my simplistic view is, when you are the opposition party you generally a) say the opposite of what the party in power want to do b) don’t have to take any actions so say what they think people want to hear. The party in power generally need to make some decisions.
In this instance his old view may be what he thinks is the right thing, but today he now recognises there are other considerations which means he has to take a different view aka if this boasts the economy, that may now be more important that waving the climate flag at it.
In an ideal world they give it the green light but ensure the solution deals with climate impact as much as possible, to slightly offset how bad flying is for the climate. Ie give priority to airlines who are improving the climate impact of their planes