AirlineRatings.com keeps tabs on 385 carriers from across the globe, measuring factors including the airlines' crash and serious incident records, and age of their aircraft.

"The challenge this year was the number of airlines that were flying, although our Top 20 safest airlines have all continued to fly or had limited cessation of flights," said AirlineRatings editor-in-chief Geoffrey Thomas.

For 2021, the airline safety and product review website awarded Aussie airline Qantas the top spot.

AirlineRatings highlighted Qantas' commitment to retraining pilots ahead of a return to service after time out during the pandemic.

AirlineRatings found that a Qantas 737 pilot must undergo a six day course ahead of returning to the skies, including a day focused on wellbeing.

Winning streak

Qantas held the title of world's safest airline from 2014 to 2017. In 2018, AirlineRatings said it could find no clear winner and chose to rank its top 20 equally, but once again in 2019 and 2020 Qantas was crowned world's safest carrier.

On some previous occasions, AirlineRatings has chosen its winner and then listed the rest of the top airlines alphabetically.

But for 2021, the website has ranked each of the top 20 airlines in numerical order.

Qatar Airways takes the number two spot, while Air New Zealand, Singapore Airlines and Emirates round out the top five.

Thomas said that the rating system was slightly adjusted this year, to allow for greater accuracy.

"Over the past two years we have become aware that some airlines, which had passed bi-annual safety audits, were not on a day-to-day basis following the operational disciplines required by the auditors," Thomas said.

AirlineRatings also looked into airline fraudulent pilot license scams and bribery allegations, added Thomas.

As a result, they decided to do a five-year audit of serious safety incidents to narrow down the top 20.

"Accidents and incidents make up five of our seven star rating with audits accounting for one and Covid-19 compliance the final star for a maximum seven-star ranking," says Thomas.

Thomas adds that travellers are even more focused on airline safety in the wake of the pandemic.

"They are not taking anything for granted and our inquiry level has tripled over the past six months on a variety of safety issues, not just Covid-19," says Thomas.

Separately, AirlineRatings also spotlighted the safest low cost airlines, listing the top 10 in alphabetical order.

They are Air Arabia, Allegiant, EasyJet, Frontier, Jetstar Group, Jetblue, Ryanair, Vietjet, Westjet, and Wizz Air.