Pyongyang, North Korea (Associated Press)-If passengers of Koryo Airlines ignore the prohibition on taking pictures, the flight attendants may pick up the camera and delete the pictures themselves. Crushing newspapers with the image of North Korean leader Kim Jong Un may bring severe admonitions to travelers, or even worse.

These are one of the many quirks that may help explain why North Korean Airlines has won a unique honor: it has been named the worst airline in the world for four consecutive years.

Koryo Airlines is the only airline to receive only one star in the ranking recently released by the British SkyTrax consulting agency. More than 180 airlines are included in the five-star ranking system, which is considered by some to be the benchmark for global airline standards.

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Some experts and regular customers of Koryo Airlines disagree with the title of "the worst in the world". They said that this airline is definitely a unique journey, but quite reliable. SkyTrax ratings focus on service rather than safety.

"Actually, it's a bit of a smirk. They are obviously not the worst airline in the world," said Simon Cockerell of the Korea Group, a Beijing travel agency that specializes in North Korea. The agency has nothing to do with Koryo Airlines, although Cockrell and his tourists often take the airline's flights.

Cockerell said that the weaknesses of Koryo Airlines are often what SkyTrax is concerned about: the foreign language of the flight attendants is not very good, the meals will not win any awards without in-flight magazines, and on old aircraft, the condensate from the cooling system tends to get wet. The seat dripped onto the passenger.

"This is not Emirates," he said, referring to the four-star Dubai Emirates according to SkyTrax. "This is not the flying experience people are used to."

Inflight entertainment is usually limited to the popular Peony Peak female group singing patriotic carols. Or a North Korean cartoon, displayed on a drop-down screen connected to the ceiling of the cabin. In less than two hours away from Beijing, there are all kinds of meals. It is similar to a hamburger.

But Koryo Airlines is not what it used to be.

Its fleet of four aircraft used on international flights is a surprising new aircraft acquired in 2008. Lax practices, such as not announcing when the plane is about to land or skipping the safety demonstration before takeoff, were resolved long ago. The new airport terminal has been greatly improved from the temporary warehouse-style buildings that have been used recently, providing passengers with a business class lounge.

At the same time, being a flag carrier of a country shunned by most parts of the West is detrimental to the airline's image. Air Korea’s only regular international destinations are Beijing, Shanghai and Shenyang in China and the port of Vladivostok in Russia.

"I'm not sure if I have seen or heard any mention of Korean Air's insecurity, but its service is terrible," Patrick Smith, an airline pilot and author of the Ask The Pilot blog, said in an email. Before the Associated Press’s latest ratings are released.

"Everything about North Korea is treated as a joke, so we should expect its airlines to be treated the same way, right or wrong," he said, warning that he has never actually flew on Koryo Airlines. "Some of the best and safest airlines in the world are airlines that ordinary Americans have never heard of."

Smith pointed out that Koryo Airlines' fleet is mainly Russian TU-204 and AN-148, which may not be as comfortable or efficient as their counterparts made in the United States or Europe, but they are not unsound.

In fact, getting passengers to their destinations-one by one-may be the strength of Koryo Airlines.

The only known fatal accident occurred in 1983, when the airline was still named CAAK. According to Harro Ranter, founder and director of the Aviation Safety Network, this is a private independent foundation that has compiled more than 10,700 incidents. The detailed description of the hijackings and accidents goes back to the 1950s.

Rand warned that the absence of fatal accidents in 32 years does not necessarily mean that airlines are safe.

"An important factor in airline safety is the state's ability to conduct appropriate safety oversight, and the level of implementation of international aviation standards and regulations," he said in an email to the Associated Press. "It is very difficult to rank airlines based on safety. Over the years, the level of global aviation safety has improved significantly, so it is impossible to make any comparisons of accidents or fatalities."

However, he pointed out that in the 2008 ICAO audit of the implementation level of international aviation standards and regulations, North Korea scored higher than the world average in most aspects. This is the latest data available.

"If these results are still valid, there is no reason to believe that Koryo Air will be unsafe," he said.