I don't know how much reliable that link is. I too was wondering how can bitcoin benefit airport authorities at a time when its price is fully volatile. Yesterday btc was 56k and today its 60k, don't know what it will be tomorrow. To be accepted as mainstream payment system we need price stability and that's something missing badly in BTC right now.
Indeed, since when has the price of Bitcoin been like the stability of the dollar value. Obviously it is highly volatile and with a relatively fast rate of volatility. But if it only refers to the price of Bitcoin then any authority will not accept it as payment. Therefore, Bitcoin is used as a legal means of payment in view of the value of the signature and the increasing price level.
The time span also needs to be considered, the airport may accept Bitcoin payments only for long-term holdings.