U.S. and Canadian authorities said they have broken up smuggling rings that used air drops to move tons of drugs across the border, a method that has become more prevalent with tightened security at traditional crossings.

In the past two years, authorities have arrested more than 40 people, and seized roughly 4 tons of marijuana, 805 pounds of cocaine, three aircraft and $1.5 million in cash.

During a news conference Tuesday at the Bellingham International Airport, officials played surveillance video from a camera hidden in a remote clearing in the Okanogan National Forest to illustrate the smugglers' methods. It showed a helicopter with hundreds of pounds of marijuana lashed to its skids swooping in before dawn last summer, unleashing its load without landing, and flying off again. A man was waiting at the clearing with a pickup truck.

"The smugglers are exploiting the terrain after we put a lot of pressure at the ports of entry," said U.S. Immigration and Customs Enforcement Special Agent Peter Ostrovsky, who worked the case.

Leigh Winchell, special agent in charge of Immigration and Customs Enforcement in Seattle, said the smugglers have been so brazen that they took a reporter for Playboy magazine on drug-running flights.

Playboy published an article last July describing smuggling operations similar to the ones described by border agents. In it, one smuggler was quoted as boasting that they were "better than Fed-Ex" and could deliver "anywhere in the state of Washington."

"I don't read Playboy magazine," Winchell said. "But I would be lying if I said we didn't take it as an affront."

U.S. Attorney John McKay said ring leader Robert Kesling has been sentenced to 17 years in federal prison. More than a dozen others have already been sentenced — including Mark Vanderveen and James White, lawyers who accepted drug money as payment — and others are awaiting trial or sentencing.

Drug smuggling operations based in British Columbia that were targeted in the investigation used helicopters and airplanes to drop drugs at prearranged sites throughout the region, including locations in the Mount Baker-Snoqualmie National Forest and the North Cascades National Park, officials said.

Julie Myers, Homeland Security assistant secretary for immigration and customs enforcement, said the means the smugglers used showed a measure of desperation in response to beefed-up security on the ground.

"They couldn't walk across the border. They couldn't drive across," she said.

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In many cases, the pilots involved were inexperienced and unlicensed. In the past 13 months, two helicopters crashed, killing three people.

During the investigation, U.S. and Canadian enforcement teams intercepted more than 17 drug shipments, including one in February 2005 involving five suitcases packed with more than 328 pounds of cocaine. It was the largest cocaine seizure in Washington state last year.