Lost luggage? Canceled flight? There's not much more that can ruin a vacation. And if you're flying on one of these airlines, you may want to prepare yourself for a few inconveniences. AirHelp, a company that helps passengers secure compensation for delayed, canceled or overbooked flights, published its annual Global Airline Rankings, which lists 72 of the world's best-known airlines from best to worst based on a composite score.

How scores were calculated

By evaluating individual airline data, AirHelp assessed airline performance and composed a score based on three factors: on-time performance, service quality and claim processing; each factor contributed to 33.33% of the final score, with 10 being the highest possible score an airline can achieve. Flights that departed within 15 minutes of its published departure time and arrived within 15 minutes of its published arrival time were considered as 'on-time'. To evaluate service quality, AirHelp worked with Attest, an intelligence platform, to survey over 40,000 people in more than 40 countries. The survey asked the consumers to rate airlines they traveled with on aircraft comfort, helpfulness of crew and food offerings. Lastly, AirHelp rated airlines on how well they processed customers' claims for compensation, including claim handling, claim turnaround and claim payout. Above, the slideshow illustrates the 10 lowest-scoring airlines from AirHelp's Global Airline Ranking. Related:

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