A multi-agency, bi-national exercise involving airborne terrorism over the U.S. and Canada took place at Whidbey Island Naval Air Station yesterday, part of a NORAD-sponsored annual event to sharpen the skills of those with a hand in homeland defense.

Called Amalgam Virgo, the exercise is “small scale, live-fly,” training coordinated by the North American Aerospace Defense Command, said a release from NORAD.

The purpose of the training is to allow U.S. and Canadian agencies to “test, improve and validate their coordination and operational procedures.”

The exercise was planned prior to the terrorist attacks in the United States on Sept. 11, 2001, during which suspected al Qaeda terrorists crashed American civilian airliners into the World Trade Center twin towers, the Pentagon and a field in Pennsylvania.

“The exercise does not indicate an increased threat to the domestic airspace of either the United States or Canada,” the NORAD message said.

About 300 people from the Federal Bureau of Investigation, the Royal Canadian Mounted Police, the Federal Emergency Management Agency, Transport Canada, the Transportation Security Administration, the Federal Aviation Administration, the Vancouver Airport Authority and Delta Airlines took part in the training aimed at improving preparedness and interagency coordination, as well as to prepare for a variety of threats and contingencies.