Story highlights

NEW: Organizers say the trip may be done by 2 to 5 a.m., hours later than planned

NEW: Despite trimming trees in advance, more pruning is done en route, causing delays

Thousands of spectators line the route, as the hulking orbiter meanders on

"This is a history-making moment here," a flag-toting spectator says

Los Angeles CNN  — 

Move over, Oscars. Take a seat, Disney. And forget the televised car chase.

The space shuttle Endeavour is conquering a new frontier – the entertainment capital of the world – and it’s getting royal parade treatment.

Like a king carried in a chariot, throngs of spectators packed the streets and lined rooftops Saturday as the Endeavour lumbered through Los Angeles on its way to retirement in a local museum.

Yet lumbering may be an overstatement. Organizers had expected the shuttle would saunter 12 miles over two days at 2 mph (most humans walk 3 mph), with several rests.

In fact, it’s progressed slower than that. By 7 p.m. PT (10 p.m. ET), the space shuttle was hours behind schedule. Organizers said they now expect it will be at its final destination between 2 a.m. and 5 a.m. Sunday – a far cry from the 10 p.m. Saturday end time that was originally planned.

This is despite advanced efforts to make room for the shuttle, which is 78 feet wide and 122 feet long. Officials had ordered 265 trees to be cut down, 67 traffic signals to be dismantled and 48 mast arms to be removed just to accommodate the shuttle.

But once they hit the road, they found more trees needed to pruning to protect Endeavour’s exterior, hence the delay.

That slow movement has allowed a festival of gawkers to line the streets and express awe as the hulking orbiter barely cleared utility poles and its five-story-high tail passed the corner glass suites of office buildings.

Endeavour’s final journey, are you there?

The remaining trees and traffic poles – as well as buildings – are now the subject of dramatic video and photography as the shuttle’s wings slowly pass within a mere inch of striking them.

“This once-in-a-lifetime event is a cause for celebration,” Los Angeles Mayor Antonio Villaraigosa said.

Gwendolyn Crews, the owner and director of Juniorversity Preschool in Compton, bought an American flag to wave at the passing orbiter. She plans to take her entire preschool to see the Endeavour settle into the museum.

“I think this is a history-making moment here in Los Angeles, California, and I want to be able to share this with my kids, my grandkids, my great-grandkids of this great event – and the children of our school,” Crews said.

Latasha Covington and her children, 9-year-old Skilyn and 4-year-old Amarie, brought a chair to stand on to get a view over the crowds.

“I’ve been here 32 years in L.A. and I’ve never seen anything like this, so it’s part of history. I wanted them to see that,” Covington said.

Richard Plump of Plump Engineering Inc. was accompanying the shuttle to make sure the pressure from the transporter doesn’t stress the underground water and sewer systems.

To relieve such pressure, crews laid 2,700 steel plates on parts of Endeavour’s route.

“I’m part of the convoy, so I am ahead. As the transporter is coming along, I’m there as another set of eyes to make sure that the transporter’s wheels are on the steel plates at the right location,” Plump said.

“I think it’s breathtaking,” he said.

Road crews erected orange signs whimsically drawn with a shuttle silhouette and the cautionary advisory “SHUTTLE XING.”

Along the route, jazz musicians played out of a garage as the shuttle continued its snail’s pace.

The transport is the largest object ever moved through the streets of Los Angeles.

The 12-mile slow trek started early Friday from Los Angeles International Airport.

More than 15,000 spectators attended a celebration outside the Forum arena in Inglewood where the spacecraft and its road crews enjoyed one respite Saturday morning, said police Lt. James Madia.

An afternoon stop in south Los Angeles will feature a performance produced by actor-choreographer Debbie Allen.

And it wouldn’t be Los Angeles without a little product placement: A Toyota Tundra half-ton pickup truck pulled the shuttle Friday night over a bridge above Interstate 405. The shuttle and its transporter platform together weigh 170,000 pounds, or more than 80 tons.

In that feat, the highway to Los Angeles International Airport was shut down, preventing any motorists from possibly causing hazards by slowing down to photograph the spectacle, illuminated with stadium-strength spotlights.

Utility workers observed the procession while perched high in cherry pickers. Some power lines had to be temporarily disconnected, and crews were waiting to reconnect the overhead lines once the Endeavour passed through.

Turning corners was mesmerizing, especially in neighborhoods of single family houses.

In an Inglewood neighborhood at Crenshaw Drive and 84th Place, the shuttle faced one of its most challenging sections – a residential street designed more for four wheels than two wings – and was on a course to strike a tree.

But transportation crews maneuvered the vehicle, with little wiggle room, to spare the tree from a chainsaw. The shuttle cleared the 20-foot tree by a couple of inches.

The cutting down of trees has been controversial in some areas, but officials say they will plant two new trees for every felled one.

The spacecraft is expected to arrive late Saturday at the California Science Center, where it will be put on permanent display.

A short history of Endeavour

Officials planned the logistics of the move for months.

Endeavour, along with Discovery, Enterprise and Atlantis, became a museum piece after NASA ended its 30-year shuttle program in July 2011. All four shuttles have been permanently retired from service.

Named for the first ship commanded by British explorer James Cook, Endeavour rolled out of an assembly plant in Palmdale, California, in 1991 at a cost of $1.7 billion. It was the baby of the shuttle fleet, built as a replacement for Challenger, which exploded shortly after its 10th launch.

Over the next 20 years, Endeavour flew some of the highest-profile shuttle missions, covering nearly 123 million miles in 25 flights. It flew a Spacelab mission and numerous International Space Station assembly missions and rendezvoused with Russia’s Mir Space Station.

The science museum has been trumpeting the arrival of the shuttle, saying on its website that it is building a new addition to its facility and plans to begin displaying Endeavour on October 30.

Read more space and science news on CNN’s Light Years blog

CNN’s Kimberly Segal, Sara Weisfeldt, Casey Wian and Joe Sterling contributed to this report