Safety is not a huge concern when flying with world-renowned airlines such as Etihad Airways, Emirates, British Airways or Cathay Pacific.

After all, their planes take off in their dozens around the world each day without a blip and their financial clout means fleets have been updated with the latest in aviation technology.

Those three carriers, along with 17 others, were recently named the world's safest airlines by AirlineRatings.com in its annual rankings.

But where there is a group at the top of the table, there also has to be a group at the bottom, and the safety and product rating website revealed its lowest rated airlines for safety in 2018 from the 409 it monitors.

Those rated one star were: Air Koryo, Blue Wing Airlines, Buddha Air, Nepal Airlines, Tara Air, Trigana Air Service and Yeti Airlines.

In the case of Buddha Air, the airline has been unable to undergo a formal IATA Operational Safety Audit (IOSA) and become registered "as there are certain IOSA requirements which Buddha Air cannot comply with, through no fault of its own" it said on its website.

However, it states that it still wishes to be measured against world airline safety standards, and also highlights the increasing problem of bird strikes in Nepal.

Meanwhile, AirlineRatings.com editor-in-chief Geoffrey Thomas explained the thinking behind how the rankings are compiled: "All airlines have incidents every day and many are aircraft manufacture issues, not airline operational problems. And it is the way the flight crew handles incidents that determines a good airline from an unsafe one. So just lumping all incidents together is very misleading."

The website describes itself as "the industry standard for safety and product rating".