When the iron gate swung open and the crowd finally got the chance to go onto the tarmac, 89-year-old Bill Giambrone made a beeline for the B-24 Liberator basking in the afternoon sun.

This was Monday at the Chester County G.O. Carlson Airport. Three antique warplanes - a B-17 Flying Fortress, a P-51 Mustang and the tall, ungainly B-24 - had floated down from a clear, limitless sky to spend three days acting as a roving monument to the 16 million Americans who served in the World War II Armed Forces, including the 1.2 million who were in the Army Air Forces.

Giambrone, a retired Norristown barber, practically shone with excitement as he ducked under the tail of the B-24 and climbed a five-step ladder into the belly of the bomber.

"It was 1944, the last time I was in one of these," he could be heard saying as his head disappeared into the hatch.

A moment later, inside the tight quarters of the aircraft, he sought to find his bearings after so many decades.

In his 20s, he had been a tech-sergeant in the 376th Bomb Group, based in Italy. As a gunner on a B-24 just like this one, he had flown on bombing raids over German-allied areas of Eastern Europe.

He now gripped the twin handles of a 50-caliber machine gun, one of 10 the plane was equipped with to ward off enemy fighter planes.

"My gun was on this side," he said, standing at the starboard waist window.

He looked around and thought for a second. Maybe it was the other window.

"I forget," he said.

He smiled.

It didn't matter.

What he did remember well was the mission over Romania in July 1944 when, "just like in the movies," German fighter planes came straight down, shooting, from "12 o'clock high." They went by so fast he hardly got off a shot of his own.

The next thing he knew, "the propellers were on fire."

He recalled trying to get the pilot or copilot on the radio. No one answered. He took his chute off the wall, strapped it over his shoulders and jumped from 20,000 feet.

Romanian citizens found him when he hit the ground, and took him to the police station. The police drove him to the plane-crash site, where the local authorities had gathered up the bodies of his eight fellow crewman - "all in pieces," he recalled.

As he said this, his gleam faded.

A little while later, back on the tarmac and sitting in the shade under one of the plane's broad wings, he was his old self again, joking with fellow B-24 veteran Joseph Verruni, also a onetime Italian kid from Norristown.

"Known him for 65 years," Verruni said of Giambrone.

For the couple-hundred other people who had gone to the airport to see the old planes, the several World War II veterans among the crowd were treated with the respect given to generals and admirals.

"We're dying like flies," said another B-24 veteran, George Ziegler, 87, of Thorndale.

That's a bleak simile that veterans often use to describe the gradual disappearance of the World War II generation.

It's true, the numbers are diminishing. Of the 16 million who served in World War II, the V.A. estimates that only 1.98 million are still alive, including 110,000 in Pennsylvania and 55,000 in New Jersey.

But the V.A. also estimates that World War II veterans will be around for a long time to come. It projects that 270,000 will be alive a decade from now, in 2020, and that a few hundred will still be alive a generation from now, in 2035.

Savage Frieze III, son of a World War II Army Air Forces veteran, accompanied his father to the airport Monday to see the old planes, owned by the nonprofit Collings Foundation, which takes them around the country as flying museum pieces.

"It's hard for my generation to understand what they went through," he said of veterans like his dad, Savage Frieze Jr., of Kennett Square.

A clergyman in the United Church of Christ, the son, 55, said he once read a book by Hannah Arendt in which the scholar coined the term "banality of evil" to describe the apparent ordinary-ness of the German people who had committed the Nazi crimes of World War II.

Frieze said he liked to think of the veterans he meets - many modest and easygoing - as representing "the banality of greatness" he finds in the Americans of that generation.

"I think that's what I'm celebrating," he said. "Ordinary people doing extraordinary things."

Contact Tom Infield at 610-313-8205 or tinfield@phillynews.com.