If you read the article it clearly states they were in that group the pioneered the original flight and were making it again 


"Pilot Marshall Severson of Anchorage and passenger Dan Billman, who owns a lodge on Lake Louise, flew an air route that both helped pioneer more than 15 years ago.

The route has remained open ever since, regardless of current tensions, such as federal investigations into Russian hacking and Russian bomber incursions into Alaska airspace."