If the sky seems thick with the sounds of aircraft Wednesday night — F-16s, C-21s, hulking helicopters — don’t be alarmed. It will most likely be part of a scheduled exercise designed to help maintain the nation’s air defense network.

The operation known as Falcon Virgo is scheduled to take place between midnight and 1:30 a.m. and will involve planes and helicopters from Civil Air Patrol, Air Force and Coast Guard fleets.

Falcon Virgo usually attracts the notice of Washingtonians, who sometimes find their sleep disturbed by the sound of F-16s and other aircraft.

The training exercise is coordinated by the North American Aerospace Defense Command (NORAD) and its regional component, Continental United States NORAD Region.

NORAD has conducted such events throughout the country and Canada since the 9/11 terrorist attacks.

In the event weather causes a delay, the event will be held overnight Thursday, officials said.