Flying for many has become full of delays, cancellations and other travel woes, but there are some airports that are worse than others when ranked by air-travel hiccups.

Most of the 100 busiest airports worldwide have had at least 20% of their flights delayed, according to flight-data specialist FlightAware, which measured flights between June 1 and July 24. At two Canadian airports, Toronto Pearson International Airport and Montréal-Trudeau International Airport, more than half of departing flights were late.

FlightAware’s data set covers the world’s top airports measured by number of flights. The delay percentage is the share of an airport’s completed departures that arrived more than 15 minutes late at their destination, according to the data provider.

Chicago Midway International Airport had the worst mark for U.S. airports, as 38.3% of its flights were delayed, FlightAware said. Also high on the list for U.S. airports was Florida’s Orlando International Airport, New York’s John F. Kennedy International Airport and the Baltimore/Washington International Thurgood Marshall Airport, or BWI.

Not all of the large airports on the list are struggling. For example, at Tokyo International Airport—known as Haneda—8.3% of scheduled flights have been delayed.

Delayed flights are one of a number of problems air travelers have grappled with this summer. They have also been inundated with lost baggage and canceled flights even as demand for travel has increased during the third year of the Covid-19 pandemic.

Here is a list of how the world’s busiest airports stack up when it comes to delays: https://www.wsj.com/articles/the-worst-flight-delays-at-the-worlds-busiest-airports-see-the-list-11658889826?no_redirect=true

Check for flight delays and cancellations: https://flightaware.com/live/cancelled

By Nate Rattner at nate.rattner@wsj.com and Allison Prang at allison.prang@wsj.com