A midair collision involving two small planes in southern Arizona killed two people Wednesday morning, authorities said.

Federal air-safety investigators said each plane had two people aboard when they collided at Marana Regional Airport on the outskirts of Tucson.

One plane landed uneventfully and the other hit the ground near a runway and caught fire, said the National Transportation Safety Board, which is leading the investigation and cited preliminary information before its investigators had arrived.

The Marana Police Department confirmed that the two people killed were aboard one aircraft and said responders did not have a chance to provide medical treatment. Sgt. Vincent Rizzi said the two people on the other plane were uninjured.

The municipal fire department helped extinguish flames, Rizzi said.

Neither the Lancair nor the Cessna 172 was based out of the airport, according to a statement from the town of Marana.

The collision came more than a week after a plane crash in Scottsdale killed one of two pilots of a private jet owned by Motley Crue singer Vince Neil. That aircraft veered off a runway and hit a business jet.

It also followed four major aviation disasters that have occurred in North America in the last month. The most recent involved a Delta jet that flipped on its roof while landing in Toronto and the deadly crash of a commuter plane in Alaska.

In late January, 67 people were killed in a midair collision in Washington, D.C., involving an American Airlines passenger jet and an Army helicopter, marking the United States’ deadliest aviation disaster since 2001. Just a day later, a medical transport jet with a child patient, her mother and four others aboard crashed into a Philadelphia neighborhood on Jan. 31, exploding in a fireball that engulfed several homes. That crash killed seven people, including all those aboard, and injured 19 others.

The airport in Marana has two intersecting runways and operates without an air traffic control tower.

A multimillion-dollar project was underway to build a tower but delays due to the COVID-19 pandemic pushed back construction. Tens of thousands of flights arrive and depart from the airport annually.

Most airports in the U.S. do not have air traffic control towers, only those with commercial traffic coming in.

At those airspaces, pilots use a designated radio channel to announce intentions for landing and taking off, said Jeff Guzzetti, an airline safety consultant and a former Federal Aviation Administration and NTSB investigator.

Just because an airport doesn’t have a control tower doesn’t mean it’s unsafe, he said.

“All the pilots should be broadcasting on this common traffic advisory frequency. And there’s also a responsibility to see and avoid. Each pilot is responsible to see and avoid so they don’t collide with each other,” Guzzetti said.