Akademik

n.

The airspace in the immediate vicinity of an airport.

"The night sky over LAX was alive with moving lights as dozens of planes waited in the birdcage for their turn to land."

Officially called the "terminal control area," another name for this airspace is "upside-down wedding cake," because the waiting planes are stacked at multiple altitudes and the higher the altitude the wider the circular flight path the plane must follow.