YENIKOY, Turkey — Looming like a fortress over the Black Sea, Istanbul’s new airport has been engineered to provoke awe, underscoring Turkey’s desire to reclaim its imperial glory.

The project is expected to cost nearly $12 billion and carve six runways across a swath of land as big as Manhattan. When completed in a decade, the complex is supposed to transport some 200 million people a year, dwarfing all rivals as the busiest airport on the planet.

But the airport has also become a symbol of a less savory aspect of Turkey’s modern-day incarnation: its reckless disregard for arithmetic and the independence of critical government institutions. Together, they have placed the nation at growing risk of sliding into a financial crisis.

In a global economy increasingly plagued by worries — from an unfolding trade war to higher oil prices — Turkey may present the most immediate cause for alarm. The country’s president, Recep Tayyip Erdogan, who has dominated national life for 15 years, was sworn in again on Monday following a re-election victory that came with extraordinary new powers. He has wielded his influence to deliver relentless economic growth through unrestrained borrowing, lifting debt levels to alarming heights. And the additional authority he has been granted is expected to further test the limits of economic reality.