They need to be handled with humanity.
Norman Foster lifted the roof of Stansted airport (opened in 1991) so gigantic glass walls could interconnect each person and space, and flood them with the same light. Its volume, grace and optimism encourages everyone to breathe with the building. I normally fly in rather sad from Knock airport, which floats on the vast Mayo bog in Ireland and has one of the most beautiful sites in the world. But Stansted's human modernism encourages me back to the metropolis.
An airport is only another theatre, and in the theatre height is always part of the intimacy equation. Oddly, it is the very height of the Bouffes du Nord in Paris that makes it so intimate. The energy lifts, instead of shooting out sideways in aggression. We breathe more freely; we collide less.
And then there is Heathrow. The approach could be worse - the model of Concord and the tunnel beneath the runway give some sense of occasion. But the buildings manage to be gigantic and claustrophobic at the same time, because there is never enough height. You are compressed in low-ceilinged corridors, disoriented and blinded by artificial light. You cannot find your coordinates so the sense of being lost multiplies. Being cramped from above makes you long for the relative peoplelessness of a business lounge. The definition of a bad public building must be that it makes you want to be on your own. A great public building makes you want to feel part of the group.