BOISE, Idaho (AP) — After the two Navy jets collided in midair, the planes sandwiched together, all four crew members were able to eject and deploy their parachutes, floating down to safety as the aircraft careened into a field, exploding into a fireball.

The collision happened Sunday during the "Gunfighter Skies" air show at the Mountain Home Air Force Base some 57 miles (92 kilometers) southwest of Boise.

Here are some things to know about the crash.

Just one crew member was injured

Only one of the four crew members on the two planes was injured and was being treated at a hospital, Cmdr. Amelia Umayam, spokesperson for Naval Air Forces, U.S. Pacific Fleet, said Monday. The injury was not life-threatening.

The fact that all four were able to safely eject and make it to the ground without landing in the wreckage is "truly remarkable," said Billie Flynn, a former F-35 senior test pilot and demonstration expert.

"It is astonishing considering the way the airplanes impacted each other — incomprehensible even," Flynn said.

The two U.S. Navy EA18-G Growlers were from the Electronic Attack Squadron 129 in Whidbey Island, Washington. Each held two crew members.

The EA-18G Growler, measuring just over 60 feet (18.5 meters) long, made its first flight in August 2006 and was the first newly designed electronic warfare aircraft produced in more than 35 years, according to the Navy. Its "baptism of fire" was in 2011 in Libya, according to the Navy, and since then it's been used worldwide.

The planes appeared sandwiched together before the crash

Videos taken by spectators show one of the jets was slightly behind the other before impact, and the two aircraft then appeared to become sandwiched together, with the belly of one jet just behind and to the side of the top of the other jet.

The jets then twisted and rocked together, pointing straight up for a moment before turning downward and falling to the ground. The subsequent impact resulted in a fireball, black smoke rising into the sky.

The crew members ejected in quick succession with their parachutes opening as the jets began to pivot toward the ground.

The cause of the crash is not yet known

Videos of the collision suggest human error is to blame, Flynn said.

Before colliding, Flynn said the video shows they were trying to line up closely — wing tip to wing tip — but failed to safely rejoin in formation, a routine maneuver.

"This is clearly a pilot error," Flynn said.

Officials have not yet released any information about what may have contributed to the crash. The incident is under investigation, Umayam said, and efforts to recover the damaged aircraft are underway.

"Our priority is to ensure the safety and well-being of our personnel, as well as security of the aircraft during the recovery," Umayam wrote in an email to The Associated Press.

The skills used in air show performances are different from those used in day-to-day routine flying or flying in combat, Flynn said. He calls it "the difference between showmanship and airmanship."

That's why most military air show crews are assigned to just do display flights during the show season, he said.

The Growler display flight crews are all flight instructors from Whidbey Island. Their core duties generally include training pilots and electronic warfare officers from the Navy, Marine Corps and Air Force.

Air shows are inherently dangerous

Pilots who perform at air shows are among the best, but there is little room for error, said aviation safety expert John Cox, who is CEO of Safety Operating Systems.

"Air show flying is demanding. It has very little tolerance," Cox said. "The people who do it are very good and it's a small margin for error. I'm glad everybody was able to get out."

The air show industry has been working to improve safety for years at the roughly 200 events held each year in the U.S. The last fatal crashes at an air show came in 2024 when two people were killed in separate accidents at different events.

This year's Gunfighter Skies event was the first at the base since 2018, when a hang glider pilot died in a crash during an air show performance.

In 2003, a Thunderbirds aircraft crashed while attempting a maneuver. The pilot, who was not hurt, was able to steer the plane away from the crowd and eject less than a second before it hit the ground.

Between 1991 to 2006, there was an average of 3.8 deaths a year at a U.S. air show, said International Council of Air Shows president John Cudahy. That number has been steadily improving and since 2017 there have only been an average of 1.1 deaths per year.

Ejecting is a complicated and dangerous process

Ejection seats use a complex system of motors and parachutes to propel crew members away from a plane during an accident. First the canopy is pushed away from the aircraft with a blast so that it poses no danger to the crew members. Then the seat itself is launched upward and out of the plane, using solid rocket motors, before the parachute deploys and the seat drops away as the crew member descends to the ground.

"You've got to have enough altitude, you've got to be clear of any obstacles and then even after all that's successful, you can injure your back," said aviation expert Jeff Guzzetti. "Just the massive, propulsive force of the ejection seat can compress the spine, or your limbs may flail."

Guzzetti said ejections are sometimes not possible during midair collisions because the damage to aircraft can be too extensive. But the way the two Navy planes came together slowly in the Idaho collision may have allowed them the opportunity to eject, he said.

"If they had hit each other at a faster speed, they would have done structural damage and the airplane would have come apart," he said.

The two Growlers were using a seat manufactured by the U.K-based company Martin-Baker, the company said Monday. Martin-Baker described itself as the leading manufacturer of ejection seats, including seats used by the Navy since 1958. The company says its seats have saved the lives of more than 2,000 Navy crew members in that time.

The explosiveness of an ejection puts tremendous force on the crew member -- as much as 20 times the force of gravity, said Michael O'Donnell, a former Federal Aviation Administration official who also worked on ejection seats in the Air Force. That's enough force to temporarily make a person about a half-inch to one-inch (a few centimeters) shorter after ejection, he said.

"A really, really bad roller coaster ride is not even close to that," O'Donnell said. "It's a good possibility that you'll be unconscious when the ejection is complete, and they may regain consciousness on the way down in the parachute."

The Growlers are irreplacable

The plane remains the Navy's most advanced airborne electronic attack tool, according to the Electronic Attack Squadron (VAZ) 129's website. The squadron is stationed at the Naval Air Station Whidbey Island, where it maintains 55 of the specialized planes.

But Boeing stopped building new Growlers several years ago. It's not yet clear how much the military will be able to salvage from the planes that crashed at the show.

"These are invaluable national assets," Flynn said. "There is no newer version of these — they are a very special, very powerful electronic warfare platform, and there's never enough of them. And now we've lost two."