Glacier International Airport was busy Wednesday as planes started arriving for this weekend's Mountain Madness Air Show. One critical piece of safety equipment was put in place and tested, which will stop fighter planes in a matter of seconds.

"We tested the emergency stopping system that engineers of the Montana Air National Guard's 219th Red Horse Squadron have been installing in the last week," said First Lieutenant Ryan Finnegan.

Its purpose is to stop a plane in a matter of seconds, slowing it from over 90 miles per hour to a complete stop.

The braking system itself features a black cable stretched across the runway. As a jet lands, it uses a hook to catch onto the cable, which slows it down.

"It's basically two big brakes on each side of the runway. When the plane hits it, it applies pressure to both sides and just stops the aircraft, so it doesn't have to go into the over-run of the runway," said Maxwell Lacy, of the 219th Red Horse Squadron.

Engineers have been working all week to make sure the system is ready to be used in case of an emergency.

"The idea with that is, this weekend during the air show should any of the Thunderbirds need to make an emergency landing, the arresting gear will let them do that safely," said Finnegan.

An F-15 jet was used to test the system -- a little different than the Thunderbirds who fly F-16s.

"Thunderbird aircraft, to my understanding, was not available. This was the next best option to do as realistic a test as possible to make sure this system works and would work in the case of an emergency," said Finnegan.

Organizers hope the system won't have to be used, but in the case of an emergency, it's ready to keep onlookers and pilots safe.

Airport officials tell us operations will remain normal during the air show. All flights will take off and land as scheduled. Officials are advising passengers to arrive at least two hours early because of increased traffic in the area.