Expect a busy Memorial Day travel weekend

The summer travel season begins in earnest on Friday, so if you're among the millions hitting the road or skies for Memorial Day weekend, plan accordingly.

Driving the news: San Francisco International Airport forecasts about 147,000 passengers to travel through the airport on Friday.

• On the road, expect peak traffic congestion around 11am on Friday along I-80 East as people head to BottleRock music festival in Napa, according to transportation data analytics firm Inrix .
• Meanwhile, travel times are expected to be up to 90% longer than usual, according to Inrix.

Zoom out: Nationwide, AAA projects 43.8 million people will travel 50 miles or more over Memorial Day weekend.

What they're saying: "We haven't seen Memorial Day weekend travel numbers like these in almost 20 years," Paula Twidale, senior vice president of AAA Travel, said in a press release.

Context: Memorial Day is about more than cookouts , sales and patriotic parades.

• The federal holiday commemorates military personnel who lost their lives defending the country.

Flashback: Memorial Day was originally called " Decoration Day " and was recognized as early as the 1860s after the Civil War.