San Francisco, May 26 (IANS): World War II-era planes flew over southern California to honour veterans and frontline COVID-19 healthcare workers on Memorial Day.

A total of 18 of the historic planes performed the flyover onMonday in Riverside County and soared over national cemeteries, memorial parks, hospitals, medical centre, airports and the USS Iowa Museum in Riverside County, Orange County and Los Angeles County, reports Xinhua news agency.

The salute was organized by the Commemorative Air Force Inland Empire Wing Operations, a non-profit and all-volunteer organization dedicated to the preservation of military aircraft.

A C-53D Skytrooper transport plane, manufactured in 1943 in California, participated in the D-Day invasion in 1944, and known as the "D-Day Doll", led the formation joined by C-47 Skytrain transport aircrafts, T-6 Texans trainer aircraft and P-51 Mustang fighters on the 90-minute "Thank You" tour.

Some US veterans were invited to attend as special guests of honour for the flight, said the organizer in a Facebook post.

Several flyovers have been conducted to honor southern Californian frontline workers in the past few weeks amid the COVID-19 pandemic, including the US Air Force's Thunderbirds demonstration team's formation flights over Los Angeles and San Diego on May 15.

Originally observed on May 31 and meant to honour the nearly 700,000 Union and Confederate soldiers who lost their lives in the Civil War, Memorial Day has evolved into a commemoration of all those who died while serving in the US Armed Forces.

A 1968 federal law mandating that the observance be shifted to the final Monday in May regardless led eventually to the emergence of Memorial Day as the unofficial start of summer in the US and Americans are accustomed to gathering in backyards and parks and on beaches to celebrate.