WONSAN (North Korea) • When he booked his tour, Swiss lawyer Rafael Studer had not seriously considered the option of jumping out of a Russian-made helicopter at 2,000m, strapped to a North Korean soldier.

"It wasn't really part of the plan," the 27-year-old admitted after landing his tandem parachute jump at North Korea's first aviation show held in the eastern port city of Wonsan. The two-day festival was part of efforts by the sanctions- strapped and diplomatically isolated country to boost hard-currency tourism in the Wonsan region.

Coming just weeks after the North conducted its fifth nuclear test, triggering global condemnation and the threat of fresh sanctions, the show drew several hundred foreign aviation enthusiasts who paid for brief flights in Soviet-era aircraft.

So it was that Mr Studer found himself half-hanging out the door of a Mil Mi-8 helicopter, above the newly-renovated and upgraded Wonsan airport, strapped to a North Korean military parachutist.

"There was a 'what the hell am I doing moment' and then we jumped. Terrifying at first, but then surprisingly enjoyable," he said.

Mr Studer landed gently, unlike Dutch flight instructor Niels Linthout, who landed barefoot - "I lost my flip-flops" - and face down underneath his tandem partner, much to the crowd's amusement.

A number of foreign professional skydivers took part in the show, including American Douglas Jaques, 68, a veteran of over 11,400 jumps.

The US State Department strongly advises United States citizens against travelling to North Korea in any capacity, citing a "serious risk of arrest and long-term detention".

In March this year, an American student Otto Warmbier was sentenced to 15 years of hard labour for allegedly stealing a propaganda poster from a hotel.

Mr Jacques said the travel advisory had given him "pause for thought" but the prospect of skydiving "in the most exotic location I could think of" proved too shiny a lure.

AGENCE FRANCE-PRESSE