This sort of question is always subjective and does depend on ones viewpoint. In addition it does depend on the definition of "best". For some people best is quite good quality at very low cost. For others it means the maximum number of destinations. See Skytrax rankings at the related link. However, this is just one set of viewpoints. The following airlines have top Skytrax billing, with a 5-star rating:

• Singapore Airlines
• Cathay Pacific
• Malaysia Airlines
• Qatar Airways
• Kingfisher Airlines
• Hainan Airlines
• Asiana Airlines

What can also affect the choice is ones frequent flier status. If a person has achieved the highest level of status on a particular airline, they will get upgraded to a higher class of service class on multiple occasions. This will tend to bias an opinion.