DOVER AIR FORCE BASE, Del. - The fallen come home here with such dignity that every American flag on every case of remains is inspected for the tiniest smudge. The dead are treated with reverence by everyone. Including their commander in chief.

For the second time in his presidency, Barack Obama was at Dover on Tuesday, saluting troops who died on his watch.

Sadness hung everywhere. For Obama, it was a day to deal with the nation's single deadliest day of the decade-long war in Afghanistan. For the families of the 30 Americans who were killed, it was a time to remember the dreams their loved ones had lived, not the ambitions that died with them.

Obama solemnly climbed aboard the two C-17 cargo planes carrying the fallen home from Afghanistan to pay respects. Their helicopter apparently had been hit by an insurgent's rocket-propelled grenade.

Later, the president consoled their grieving families. He stood in honor as the flag-covered cases were carried off the planes in front of him.

The country didn't see it.

There will be no lasting, gripping images this time of Obama assuming his office's grimmest role. No family could give permission for media coverage, the military said, because no individual bodies had been identified yet.

The helicopter crash in Afghanistan on Saturday was that horrific.

For Americans with no sons, daughters, other relatives or friends in the military, this punch seemed to blindside everyone. The war is supposed to be winding down, and the face behind it, Sept. 11 mastermind Osama bin Laden, was killed months ago by elite U.S. forces.

Saturday's blow claimed 22 Navy SEALs from the same special forces team that pulled off the remarkable mission in Pakistan that ended bin Laden. None of those killed on the helicopter was part of that raid, but the connection, along with the size of the loss, was deeply felt.

The troops who died had been flying on a mission to help fellow forces under fire.

The fallen were described as intensely patriotic, talented and passionate about the risks and responsibilities that came with their jobs.

Some were married with children. One wanted to be an astronaut. Another was going to propose to his girlfriend when he got home.

Three were from the same Army reserve unit in Kansas: Bravo Company, 7th Battalion, 158th Aviation Regiment.

Seven Afghan commandos and one Afghan interpreter were killed, too, when the helicopter crashed in the Tangi Valley.

On Tuesday, 30 cases draped in American flags came off the planes; eight others were covered in Afghan flags.

The president had flown by helicopter to Dover.

The trip was kept private by the White House until he landed as a measure of security, although expectations of his presence were high from shortly after the 30 troops died.

Upon arriving, Obama boarded one plane carrying remains to pay respects to the fallen, then did so again on the second plane.

He then met with about 250 family members and fellow servicemen and women of the dead. He spent about 70 minutes with family members, offering his condolences and gratitude for their sacrifice and service, the White House said. Defense Secretary Leon Panetta and Joint Chiefs Chairman Adm. Mike Mullen joined in.

The formal process of honoring the troops, known as a dignified transfer, rolled on across the afternoon. Reporters were kept out of sight in a nearby building.

Officials frown on calling the events a ceremony to avoid any connotation of celebration.

As described to reporters, the president and the rest of the official party, including military leaders, boarded the cargo planes. A chaplain said a prayer.

Then the president and the rest of the dignitaries stood somberly in a hangar as remains were carried out in transfer cases, one by one, along a red carpet and into waiting vans.

Out of respect, the words "coffins" and "caskets" are never used.

Teams on site ensure the cases come off the plane in perfect shape. They are carried down by personnel from each fallen member's service - and not just any troops but those specially chosen for the high honor.

Three days after the downing of the aircraft, the Defense Department has not released the troops' names. Officials say it is taking time because there were so many killed. Others say privately there is hesitancy to release the names because the majority were from sensitive special operations forces.

The military has launched an investigation into the helicopter crash. The probe will address a host of questions, including the decision to send a Chinook helicopter packed with Navy and Air Force special operations forces to a firefight to assist troops on the ground.

For the troops returning in cases on Tuesday, and so many others over the months and years, Dover personnel eventually return the bodies, if possible, to their loved ones in whatever clothing the family choses. It could be military dress. Or jeans, a T-shirt and cowboy boots.

And always, with reverence.

"It is a very big source of pride, and a sense of duty and honor that we give to the fallen service members," said Dover mortuary affairs spokesman Van Williams. "We represent the nation. And a grateful nation at that."

Associated Press writers Pauline Jelinek and Julie Pace contributed to this report.