It was a party atmosphere along Barack Obama's motorcade route from the airport after he arrived in this Central American country for his first visit as president.

Thousands of locals, who are known as "Ticos," lined the road to welcome their fourth visiting American president. The most recent one to visit was Bill Clinton in 1997.

Municipal employees were given the day off to ease traffic.

Some of those who lined the roadway — two and three people deep — waved American flags. Others held homemade signs, including one that said "Fired Up!" — a reference to Obama's campaign slogan. More crowds gathered along the route between Obama's hotel and Casa Amarilla, the headquarters for the Ministry of Foreign Affairs, including hundreds of students in school uniforms.

"We're very happy to welcome our big brother," said retiree Ricardo Marin, 62, explaining the jubilant mood. "We hope they don't neglect us, that this visit will help our country."

Obama's reception here was vastly different from Mexico. There was no major crowd presence for Obama's travels in Mexico City on Thursday and Friday.

___

Excitement over Obama's visit wasn't shared widely, however.

"I had to walk more than a mile to get to my job," grumbled Luis Humberto Rodriguez Burgos, 26, who sells cellphones in the city center, which was shuttered and empty. "There are no clients, no tourists and we're losing money. Clearly if they close the city for a foreign president, that's not going to improve my working conditions, nor help me feed my children."

___

Obama and Costa Rica's president, Laura Chincilla, strolled to a courtyard at Casa Amarilla, or Yellow House, after they met and were greeted by about 100 schoolchildren, ranging in age from about 7 to 16. All were in uniform, and the younger ones waved U.S. and Costa Rican flags. Obama wore a broad grin as he stood encircled by the singing students.

They sang "I'm Tico" and "The First Time I Saw Limon," a reference to a city on the country's Caribbean coast.

As the children sang, thunder roared in the distance and the wind picked up.

___

After the songs, Obama praised the students, calling them "brave" and their performances "very good." He also asked for their names.

The students gushed as Obama invited them to pose for photos.

"What do we say?" he asked.

The students and Chinchilla said: "Cheese." Obama responded with, "Queso!" the Spanish word for cheese.

___

Obama opened his day by making his second visit to Mexico City's soaring, modernistic National Museum of Anthropology.

"Each time that I come, I've been inspired," he told a predominantly student audience.

Of course, last time he may have narrowly avoided getting sick.

In April 2009, Obama was he honored guest at a state dinner at the museum — just as the global swine flu outbreak was first surfacing in Mexico. Ultimately, the H1N1 strain killed thousands of people worldwide.

Obama never came down with the H1N1 flu. However, a security aide of his did — and passed it on to family members in the U.S.

___

AP White House Correspondent Julie Pace in San Jose, Costa Rica, and Associated Press writer Mark S. Smith in Washington contributed to this report.