"I remember one shoulder hurting, but other than that I didn't feel any pain. I even took a selfie," Antalffy tells CNN.
After all, he had been paragliding off and on for a couple of decades; this was just another adventure.
So he packed up his parachute and lugged the 20-kilogram bag to the highway, where he flagged someone down and got a ride back to his hotel.
In fact, it was days before he discovered that in the paragliding freefall that he doesn't even remember, he broke his scapula and numerous vertebrae; cracked his skull and blood was pressuring his brain.
The 54-year-old Hungarian entrepreneur had traveled from his home in London with a group of enthusiasts for a two-week paragliding adventure in Valadares, Brazil, though he says he has very few memories from the first week after the accident on February 23.
When Antaflffy didn't return to the hotel that night, his colleagues called the police, but were convinced he only had relatively minor injuries when he walked in the door the next morning.
After a trip to the hospital, which was overrun by a local yellow fever outbreak, Antalffy was sent back to bed at his hotel under heavy sedation. His colleagues planned to take him home on a plane in a few days time.
But in fact, the blood was accumulating in his brain and he was barely conscious, Antalffy says. In a daze, he took twice the pills prescribed.
His wife Anita Dangel, who had stayed home in London, had been unable to reach him on his phone for two days, and when she finally got through to the hotel and spoke to her husband she knew something was amiss
"He told me, 'I'm really weak. I had an accident. I'm too weak to come home, please come help,'" she told CNN.
"That was a red light for me. He's so independent; if he can do something on his own, he will."
Dangel struggled to reach Valadares -- and even then doctors told her they could fly to a bigger hospital in the nearby city of Belo Horizonte.
Intuition guided her, and they chose a six-hour ambulance drive instead.
"When we got here and they did a head scan, the doctors told us it was a miracle. He would have died if we had tried to fly with so much pressure on his brain."
More than three weeks later and Antalffy is quickly recovering. They hope to fly home at the end of the month.
"There are things that change your life forever," Dangel said. "This is definitely one of them. We will never be the same."