Two planes, one of them an Alaska Wildlife Trooper fixed-wing aircraft, collided in midair southwest of Wasilla on Saturday, and both pilots were injured in the crash, authorities and emergency responders said.

The crash was reported to Alaska State Troopers just after 1 p.m. Saturday. Multiple witnesses saw the planes collide in midair, said Clint Johnson, an investigator with the National Transportation Safety Board. A helicopter search located the crash sites about a mile apart in a wooded area near the privately owned South Hollywood airstrip, off Knik-Goose Bay Road and Vine Road.

The pilots of both aircraft were found alive but injured. No passengers were involved in the crash.

One pilot, the Alaska Wildlife Trooper, was taken by ground ambulance to Mat-Su Regional Medical Center with moderate injuries, troopers spokeswoman Megan Peters wrote in an email.

It took emergency crews two hours to extricate the second pilot, who was life-flighted to Providence Alaska Medical Center in Anchorage with serious injuries. Gene Weisman, district chief for Mat-Su emergency medical services, said that crash site was found about a quarter-mile into the woods from the South Hollywood airstrip.

"He's critical," Weisman said of the pilot's injuries. "He exhibited a lot of trauma."

Troopers said the names of the pilots are being withheld pending notification of next of kin.

Stephanie Workman, 34, lives with her husband and children on a 10-acre property that overlaps the airstrip. The area is heavily forested, with some swampy sections, Workman said.

She was checking Facebook earlier Saturday when one of her neighbors posted about a midair plane crash. She looked out her window and saw a helicopter hovering over the end of the runway at the airstrip.

Workman said her next-door neighbors immediately set out on four-wheelers to try to help. She and her husband also offered up their snowmachine.

"In the air community, even if it's somebody you don't get along with on ground, a pilot is a pilot," Workman said. "We all look out for each other."

Johnson said the NTSB would aim Saturday night to speak to witnesses as quickly as possible. The agency would work to move both pieces of wreckage out of the woods and into a secure hangar for examination.

The NTSB's task will be to find out how the crash occurred and why the pilots apparently weren't able to see each other, Johnson said.