Plane passengers are used to paying for check-in baggage or priority boarding, but one airport in Venezuela is now charging for the ultimate hidden extra - air. Anyone departing from the Simon Bolivar International Airport of Maiquetia in Caracas now faces a levy of 127 bolivars ($18) to pay for a new air conditioning unit installed earlier this year, according to a statement on the airport's website.

Airports are known for rules and regulations, a reputation that applies to the runways as well. Almost all airport designs are governed by regulations established by the International Civil Aviation Organization to ensure pilots circling Toledo or Timbuktu remain properly oriented and deliver passengers and cargo safely.