The cost of building a new international airport is astronomical, typically ranging from $1 billion to $15 billion or more, depending on the scale and complexity. For a mid-sized regional airport, costs might hover around $500 million to $1 billion. However, major global hubs require much more investment; for instance, the new Istanbul Airport cost approximately $12 billion, while the Kansai International Airport in Japan cost over $20 billion due to the engineering challenge of building on an artificial island. These budgets are split across massive categories: land acquisition and environmental remediation, the construction of reinforced runways (which can cost $100 million each), high-tech terminal buildings with advanced security systems, and "landside" infrastructure like highways and rail links. In 2026, many projects also face rising costs due to "green" mandates, requiring billions for sustainable materials, solar farms, and water recycling systems. Because of the high price tag and long timeline (often 10–20 years), most new airports are funded through complex public-private partnerships.