LOS ANGELES—Memorial Day weekend travelers have already set a new 2021 record at Los Angeles International Airport (LAX), with more than 78,000 people passing through Transportation Security Administration on May 28 alone, according to airport officials. With travel plans long-delayed due to the COVID-19 pandemic, more than 37 million people were expected to travel from May 27 through May 31, a 60 percent increase from last year’s record-low of 23 million travelers, according to data from the American Automobile Association. Even before the holiday, May was already the busiest month at LAX since early 2020 before the onset of the pandemic, with an average of 61,400 passengers passing through security checkpoints each day. That is only about half of the passenger volume from the same period in 2019, but airport officials said it is still significantly higher than it has been during the pandemic and increasing every week. LAX officials …