Those who have been on a late flight with Air Canada now have hard data to back up their complaints. The airline was ranked one of the worst in the world for punctuality by a new study. 

Compiled by Claim Compass, a website that helps organize complaints against airlines, the study looks at about 135 airlines worldwide to determine which are the worst for late complaints, both in terms of their punctuality and processing of complaints. 

Hey @AirCanada, when you delay flights by 3 hours you could I least let people buy a pass to the lounge...

— Jonathan Bardo (@jonathanbardo) April 15, 2019

The study ranks the various air service providers on a score out of 10, subtracting points for late complaints.

Dear @AirCanada:
I’ve written 9 profanity dripping drafts about my experience waiting through many flight delays for AC1659 that are too impolite to share on Twitter. Do you know how bad the experience is for it to be too profane for 2019 twitter? 3:30a arrival bad. Like DAMN.

— Mike Bickerton (@mikebickerton) March 1, 2019

Two Canadian companies made the list: Air Canada, which was near the bottom with a sad 4.5/10 score (with a flight performance score of a measly 2/10, and a complaint processing score of 7/10), and WestJet, which actually made it into the top ten, sitting comfortably at the eighth spot with 6.5/10 (flight performance score: 5.5/10; complaint processing: 7.6/10).

#aircanada the worst travel of my life, old and damaged aircraft, they lost my luggage, 12 hours added of delays. An awful nightmare. Please retweet!!!

— Mari Palma Irizarry (@aguilaelegante) April 10, 2019

According to Claim Compass, Air Canada was late to their destination almost a third of the time, by at least 15 minutes. 

Here are the best performing airlines, based on the lowest frequency of lateness and complaint processing: 

1. South African Airways (7.4/10)
2. SAS Scandinavian (7.3/10)
3. KLM (7/10)
4. Austrian Airlines (6.9/10)
5. Luxair (6.8/10)
6. Volotea (6.8/10)
7. Ryanair (6.7/10)
8. WestJet (6.5/10)
9. American Airlines (6.4/10)
10. Etihad Airways (6.4/10)

The complete results including the top and bottom performers are listed on the Claim Compass website.