A 12-year-old stowaway who wanted to go to American but ended up in Australia by mistake arrived back in Vienna Friday at the end of a 19,000-mile airborne adventure.

Kristofer Dobrowski was questioned by police and then handed back to his Polish-born mother, officials at Schwechat airport told The Associated Press. His home address was not released.Airline officials were at a loss to explain the incident but said they were checking security systems.

Dobrowski was put on a Vienna-bound plane in Australia late Thursday after he was discovered in the transit lounge of Sydney's airport without a ticket, travel papers or identity documents.

"He is knee-high to a grasshopper," said one Australian immigration officer. "It seems he wanted to go to America and mistook the Qantas flight destination of Melbourne for Miami."

Officials, using an interpreter, found that Dobrowski had flown undetected from Vienna to Bangkok, and on to Hong Kong and Melbourne before being picked up in Sydney.

Immigration spokesman Geoff Smith said officials became suspicious when they realized the boy spoke no English, was traveling alone and had no travel documents.

Dobrowski, who is Polish but lives with his mother in Vienna, said he was unhappy at his mother's recent remarriage. He said he did not like his stepfather, so he decided to run away.

"He left home Saturday and went to Vienna Airport where he somehow boarded an Air Lauda jet for Bangkok and Hong Kong," said the spokesman. "He stayed in Hong Kong for two days in the transit area, mostly sleeping while he recovered from his flight from Europe to Asia."

When he overcame his jetlag, Dobrowski tagged along with a family that was flying to Australia, apparently managing to pick up a boarding pass he found on the ground and use it to join a flight to Melbourne.