They are currently auctioned almost nowhere. Instead, they are permanently owned by incumbent airlines who never paid for them. Additionally, incumbent airlines

They are currently auctioned almost nowhere. Instead, they are permanently owned by incumbent airlines who never paid for them. Additionally, incumbent airlines lobby against slot auctions, see e. g. https://airlines.iata.org/analysis/the-dangers-of-slot-auctions https://airlines.iata.org/analysis/the-dangers-of-slot-aucti... The fact that slots are not available to newcomers is a valuable moat for incumbents.