DULUTH – Once threatened with closure due to planes passing too close to protected pines along the edge of the world's largest freshwater sandbar, Sky Harbor Regional Airport has a new runway and a clear future.

"We had to thread a needle with protecting natural resources and we were ultimately able to do that," said Tom Werner, director of the Duluth Airport Authority, which owns the airport next to Lake Superior on Park Point. "This truly was a preservation project."

A new 2,600-foot runway along Superior Bay opened Friday after three years of construction and more than a decade of planning. The $13.2 million project was almost entirely paid for by the Federal Aviation Administration, with about $1 million in state support.

The airport, used for small personal aircraft and seaplanes, is about 10 miles from Duluth International Airport. As of 2018, Sky Harbor had an average of 38 aircraft operations per day, according to federal data.

Seven acres of new land was built up along the edge of Park Point in order to angle the runway into the bay rather than toward the forest at the edge of the sand spit.

The Minnesota Point Pine Forest Scientific and Natural Area contains hundreds of pines that in recent years have grown tall enough to pose risks for aircraft taking off and landing at Sky Harbor. Rather than cut down the trees — an option met with fierce resistance among Park Point residents and the Department of Natural Resources — the 5 degree runway realignment was pursued.

"When we started this project it was not a foregone conclusion that Sky Harbor would stay open," Werner said. "Now we're making sure we can maximize growth and opportunities for aviation."

Construction began in fall 2017, and the airport was able to remain operational through nearly the entirety of the project. The runway was shortened from its original 3,050-foot length, though the additional space opens the door to more development at the airport, which Werner said is a direct contributor to local tourism.

Opened in 1939, Sky Harbor is self-funded by the pilots and businesses who use it.

"Users have been extremely pleased with the upgrades, not only to safety but also new pavement and new navigational aids," Werner said. "It also gives security for the long-term future of Sky Harbor."