U.S. President Barack Obama buys maple leaf cookies for his two daughters while stopping at Ottawa's ByWard Market. (Jim Watson/Getty)

U.S. President Barack Obama may have left Ottawa's downtown for the airport — with one of Ottawa's famous BeaverTail pastries in hand — but the memory of that one quick wave he offered from Parliament Hill will stay with many of his admirers forever.

Thousands of people gathered on the lawn of Parliament Hill on Thursday to catch a glimpse of Obama during his one-day trip to Ottawa.

"My mother wanted to come down," said Donneyl Baker, one of the 2,000 people there to see the president. "She said, 'I'm not going down if we're not going to see him.' "

Some admirers did spot Obama for a brief moment.

Before Obama entered the Parliament Buildings to meet with Prime Minister Stephen Harper, he quickly ducked out to give a quick wave from behind the Plexiglas near the doors of Centre Block.

And for that, the crowd went wild — only, not too wild.

The admirers waiting on the lawn to wave back were lined up against barricades, and had been joined by many police and RCMP officers.

People watch U.S. President Barack Obama's motorcade make its way through Ottawa's streets on Thursday. (Courtesy of David Rossington)

Police controlled access to the grounds, with officers posted at approximately five entrance gates. They searched bags, backpacks and purses, and even asked some visitors wearing bulky coats to open them.

Security was tight downtown. Mailboxes disappeared and manhole covers were welded shut. Streets were closed and the city's traffic cameras went dark.

Even before Obama landed, a car was towed from where it was parked on O'Connor Street, near Wellington Street, and RCMP arrested a 20-year-old man after he tried to jump one of the barricades on Parliament Hill.

But the enhanced security and snow that fell through the morning didn't dampen the enthusiasm of the president's admirers.

"Actually, I have three tests today that I missed," said 16-year-old Pacifique Sebaremzi. "And, frankly, if he came again tomorrow, I would do it all over again. My mom knows, but honestly, I wouldn't miss this for the world."

Obama takes a bite of Ottawa's famous pastry

Ottawa residents had been told that Obama wouldn't be making any public appearances during his visit.

But first, there was the wave — a brief connection made from behind a Plexiglas wall.

And then Obama decided to further connect with Ottawa residents by walking into the city's Byward Market to order his very own BeaverTail.

Jessica Millen delivered an Obama Tail to U.S. President Barack Obama at Ottawa's Byward Market on Thursday. (CBC)A BeaverTail — for anyone not from Ottawa — is a flat, deep-fried, doughnut-like pastry that's served all year long, but often goes best with a skate on the Rideau Canal.

As Obama's motorcade made its way to the airport, it parked briefly about a block away from the BeaverTails kiosk in the Byward Market building.

In December, the owner and co-founder of the chain, Grant Hooker, was asked by the Canadian Tourism Commission whether he would be interested in taking the treat down to Obama's inauguration.

The invite came after Hooker invented a new BeaverTail to celebrate Obama's victory. The special Obama Tail has a chocolate "O" on top.

This time, Obama came to him.

"I'd just arrived from school to work," said Jessica Milien, who was working at the kiosk on Thursday. "Next thing I knew, an agent was in front of me asking if me or my other co-worker, Fiona, could come and deliver an Obama Tail to Mr. Obama."

Milien said that her co-worker was nice enough to let her go because she is such a big Obama fan.

"That felt actually overwhelming," she said. "I have no words. I felt like I was going to pass out. I felt sick. But I was so happy at the same time."

"We had a little conversation, and I told him what his tail consisted of," Milien said. "Then he asked me my name and I told him to have a great day."

Obama's next stop was to meet with Liberal Leader Michael Ignatieff at the Ottawa International Airport before again climbing aboard Air Force One to depart at about 5:30 p.m. ET.