Veronica Lopez thought about changing her ticket, but she decided that she needed to fly on Sept. 11, 2011.

“We cannot live in fear,” said Lopez, who was born in Cuba, became an American citizen in the early 1970s and travels frequently for work. “We must continue with our lives.”

So on Sunday she boarded a plane from Reagan National Airport.

On Sept. 11, 2001, Lopez was on a flight from Puerto Rico to Florida when the pilot announced they were going back.

“There was a moment where you could hear him take a breath in, and then he said, ‘We cannot land in the United States,’ ” said Lopez, 58, who works in Fort Lauderdale, Fla. “They wouldn’t say what had happened.”

The flight set down at an airport filled with police in riot gear, and travelers crowded around televisions showing New York’s crumbling twin towers.

“It was devastating, and not only for the United States,” she said, tearing up at the memory. “Everyone was shaken.”

— Jenna Johnson

La Guardia Airport was dead, eerily so, early Sunday morning. There was no line at security, just a few travelers there to catch the shuttle to Washington.

Two people who worked for security stopped to talk. One, a woman, spoke reassuringly: “He’s flying today,” she said, referring to President Obama. Nothing, she said, would go wrong on a day when the president was flying between the two cities hit 10 years ago.

After she moved on, her partner, a man from Lahore, Pakistan, adopted a more somber tone.

“Seriously,” he said, “what I think about now is that God is waiting for us. This world is going to end and we’ll have to answer to God whether we’re Christians, Jews or Muslims. The question is, how is it going to end? How is it going to end?”

Their contrasting responses were echoed by a flight attendant aboard the shuttle.

“It’s just another day, just another day,” he said. “I’m not worried. They’re not going to do something on the same day. When they do it — and they definitely will do it — it will be a different day.”

— Norma Grill

A stream of travelers walked up to the American Airlines counter at Reagan National Airport: A sailor in dress uniform, a couple wearing hiking boots and backpacks, a guy in shorts and sandals.

As the digital clocks in the terminal flipped to 8:46 a.m. — the moment the first plane hit 10 years ago — snippets of a soft announcement floated up from a speaker. “Remember . . . who lost their lives.”

At the counter, a woman in a navy vest checked the tickets of Tom and Eileen Meyer, who were headed home to St. Louis.

Another announcement sounded, loud enough for everyone to hear, but so routine that no one took much notice: “Only ticketed passengers are permitted beyond the security checkpoint.”

The organized moment of silence ended louder than it began: “We will never forget. Thank you.”

The Meyers, both 57, wheeled their bags to the drop-off spot, unaware of the announcements.

— Jenna Johnson

Doug Bueschel, 60, was traveling from his home in Sarasota, Fla., to Baltimore for a work conference.

Bueschel, vice president of operations and quality at Rapid Halogen Screening, noticed tighter security than usual at the Sarasota airport . At least half the people going through checkpoints were asked to open their carry-on suitcases. Everyone with a laptop had to open it so a security officer could check it.

“I’m one that appreciates security, so I didn’t get bothered by it,” Bueschel said. “After they checked my computer, the security guy said ‘Thank you’ and I said ‘Thank you’ back. He seemed surprised by that.”

— Steve Yanda

Harry’s Tap Room at Dulles International Airport grew quiet during a break in the Baltimore Ravens game as a State Farm commercial played, showing schoolchildren singing the song “Empire State of Mind” to New York firefighters.

Several people said they didn’t realize the significance of the date when they booked their tickets. An Australian teenager headed to Dublin had to bump up her trip to Sept. 11 because her U.S. visa was about to expire. Two women returning to Britain didn’t realize until “news on the telly” became inundated with anniversary segments.

“I didn’t even think about it” when booking tickets, said Jamie Martin, 28, who returned to Virginia after celebrating her wedding anniversary with her husband, Derek.

— Jenna Johnson