The pilot was subsequently escorted by police helicopter back to the nearby town of Hirt, from where he had taken the light aircraft.
It was a dangerous trip in more ways than one for the trainee pilot.
The young, apparently mentally ill man took off from Hirt - just north of the Carinthian capital. He flew first towards Gurktal, then on to Klagenfurt - without radio, without permission and flying no higher than 30 to 50 feet above the ground.
When he entered the control zone around Klagenfurt airport, ground staff at Austro Control raised the alarm.
After the pilot failed to respond to radio messages and light signals, the Dragonfly police helicopter unit was called to assist.
"The air traffic controllers at Austro Control saw a power glider from the airport control tower at Klagenfurt Airport," said Markus Pohanka from Austro Control.
"The control zone around the airport may only be flown in with permission. The traffic controllers attempted to contact the pilot but he did not respond."
"It has happened before that a private plane was flown along the boundary of the control zone, but that one was flown into the control zone was exceptional," said Pohanka. "Of course, pilots know they need a permit."
Ottmar Karner, the pilot of the Dragonfly police helicopter, described the incident: "We flew along next to him and he didn't even notice us. As far as we could tell, he was staring straight ahead.
We attempted to make radio contact, but then we found he was flying towards Hirt. We notified the police and they took him into custody."
The Kronen Zeitung paper reported that the man had disappeared from a psychiatric hospital just before taking off in the plane.
After landing back at Hirt airport, the 28-year-old allowed police to return him to the psychiatric ward.
According to the Kronen Zeitung, the plane was a former military aircraft from Egypt, owned by the Hirt Aviation Association and used as a training aircraft.
Many questions remain about the incident. How could an amateur pilot simply fly off in a power glider? How well trained was he?
Karl Tengg, a flight instructor for amateur pilots, said the man was "a frequent flier who had been in possession of a valid glider pilot license for many years."
"In spring he obtained the authority to use an auxiliary engine. That is, he was actually entitled to fly the motor glider on his own, but only in the aerodrome area."
When asked whether the man took the aircraft with the knowledge of the airport's operational staff, Tengg responded that the man had "independently taken the aircraft into operation."
Airspace is divided into zones. From a safety standpoint, the most important is the control zone of an airport.
"If someone can now fly a plane into a control zone without registration, this is a dangerous state of affairs. The air traffic controllers who are coordinating things on the ground have no idea they are there," said Tengg.
"Normally there is absolutely no unregistered flying in a control zone, so this was an absolutely unique case."