World War II-era planes took to the skies over Southern California on Monday to honor veterans and frontline health care workers on Memorial Day.

Eighteen war planes will be part of the hourlong aerial tribute, called “Operation SoCal Strong,” that will fly over cemeteries and hospitals, according to a post on the Commemorative Air Force Inland Empire Wing’s Facebook page.

The aircraft took off in Riverside County just before noon, Sky5 video showed. The tribute was made its way through Orange and Los Angeles counties and was slated to land in Chino after 1 p.m.

Described as a “thank you tour,” the salut was meant to “to celebrate all 1st responders as well as commemorate those who have given so much for our freedom,” the organization said Saturday.

The Commemorative Air Force Inland Empire Wing’s C-53D named D-Day Doll, which was built in Santa Monica in 1943, led the event. Other aircraft involved included Betsy’s Biscuit Bomber, Flabob Express, The Spirit of Benovia and What’s Up Doc.

Veterans from World War II, and the Korea and Vietnam wars were invited to join as special guests of honor for the flight, according to the Facebook post.

The idea for the Memorial Day event came after recent aerial tributes across the country by the U.S. Air Force Thunderbirds and the U.S. Navy Blue Angels,  Bill Prosser, the organization’s operations manager told the Los Angeles Times.

“We’re going to be a lot slower than the T-Birds and Angels, so people can see us better. It’s not like, ‘Boom — they’re gone.’ We’ll be doing 120 mph,” he said.

The Thunderbirds soared over the Southland on May 15.

In addition to saluting veterans and first responders on the front lines of the COVID-19 crisis, the organization says the flyover has a message for everyone else.

“Our goal is to signal to all Southern Californians to remain vigilant during these challenging times as past generations have,” the post said.