This post falls into 2 categoris. The passengers and employees and building construction.
One thing that seems to make sense to me is that a happy passenger is a paying passenger. If you were able to load a plane with happy people or people who were enjoying being in your airport they’re more likely to move efficiently and cut down on times.
Another aspect to this is that happy people are willing to pay more for passenger handling and other things within the airport. This could mean higher prices and revenue from shops and vending machines.
What makes them happy? Decor! Having a well decorated airport makes people happy. No one likes a grey bleak box… talk about a distasteful travel experience. Another thing is shops (food/drink and souvenir/object) maybe a coffee to boost someone’s mood, or a favourite chocolate bar catches their eye. Maybe it’s finding that last minute gift/souvenir for someone. Higher quality stores boost happyness more and prices will reflect that. Put the prices too high though and you insult people bringing their enjoyment factor down.
A clean airport is a nice airport. Finally gives janitors a reason to clean.
And one of my favourite ideas… observation zones. You can’t deny you haven’t at least once looked out of the terminal windows at the planes taking off and landing and thought wow! A quick little boost of happyness/enjoyment before getting on the plane. Can only be zoned inside a secure zone in front of windows…