MIAMI -- A flight out of Miami is now safely on the ground in Buenos Aires, Argentina, after a high-altitude drama.

FBI agents said that the plane was about halfway to Buenos Aires when Pablo Moreira, 28, tried to get into the cockpit of United Airlines Flight 855. Moreira was reportedly kicking and hitting the 777's cockpit door, when he was able to get partially in.

"He inserted himself, you know his torso, into the cockpit. So I jumped on him and other individuals jumped on him" a passenger who was on the flight said. "What I learned later is that he was halfway into the cockpit, and then, on the other side, the copilot used an axe that they have in the cockpit to basically hit him bluntly on the head."

That passenger said that some crew members and others then carried the 28-year-old man back to business class where they tied him up with seatbelts. They then kept watch over him for the remaining three to four hours of the flight. There were 157 people on board the plane.

Judy Orihuela (pictured, right), of the Miami office of the FBI, said that witnesses aboard the plane said that Moreira did not appear to be drunk and he was not armed. She said that Moreira was injured while being subdued, but his injuries are not serious.

Orihela said that a flight attendant was also slightly injured while trying to control Moreira.

United representatives said that Moreira is from Uruguay and they believe that he was acting alone.

A statement issued by United Airline Chairman and CEO Jack Creighton says that the changes the airline made in its cockpit doors helped keep Moreira out. "The passenger never gained full entry due to the reinforced cockpit door bar United has installed on all of its fleet," the statement said.

According to the FBI, Moreira kicked in a small panel toward the bottom of the door, and stuck his head into the cockpit before he was hit, but he was unable to gain entry into the compartment.

The Miami office of the FBI says that Moreira will be flown back to Miami today. The minimum charge he will face is interfering with a flight crew, but additional charges may be added after an investigation.