And the volunteers know just how to answer, using the North American Aerospace Command program's 11-page page playbook as a guide.

But after 57 years in operation, NORAD Tracks Santa still gets a few surprises -- like the little boy from Missouri who called Monday wanting to know when Santa would deliver toys to heaven.

His younger sister died this year, his mother explained to Jennifer Eckels, one of the program's hundreds of volunteers. "He kept saying 'in heaven,'" Eckels said. She told the boy, "I think Santa headed there first thing."

Volunteers at NORAD Tracks Santa answered more than 41,000 calls by Monday afternoon and were on pace to exceed last year's record of 107,000, said program spokeswoman Marisa Novobilski.

The North American Aerospace Defense Command, a joint U.S.-Canada command responsible for protecting the skies over both nations, tracks Santa from its home at Peterson Air Force Base.

NORAD and its predecessor have been fielding Christmas Eve phone calls from children -- and a few adults -- since 1955. That's when a newspaper ad listed the wrong phone number for kids to call Santa. Callers ended up getting the Continental Air Defense Command, which later became NORAD. CONAD commanders played along, and the ritual has been repeated every year since.

NORAD usually can predict what kids will ask. Its playbook for volunteers includes a list of nearly 20 questions and answers, including how old is Santa (at least 16 centuries) and has Santa ever crashed into anything (no).

But kids still manage to ask the unexpected, including, "Does Santa leave presents for dogs?"

A sampling of anecdotes from the program this year:

THE REAL DEAL: A young boy called to ask if Santa was real.

Air Force Maj. Jamie Humphries, who took the call, said, "I'm 37 years old, and I believe in Santa, and if you believe in him as well, then he must be real."

The boy turned from the phone and yelled to others in the room, "I told you guys he was real!"

HE KNOWS WHEN YOU'RE AWAKE: At NORAD's suggestion, volunteers often tell callers that Santa won't drop off the presents until all the kids in the home are asleep.

"Ohhhhhhh," said an 8-year-old from Illinois, as if trying to digest a brand-new fact.

"I'm going to be asleep by 4 o'clock," said a child from Virginia.

"Thank you so much for that information," said a grateful mom from Michigan.

DON'T WORRY, HE'LL FIND YOU: Glenn Barr took a call from a 10-year-old who wasn't sure if he would be sleeping at his mom's house or his dad's and was worried about whether Santa would find him.

"I told him Santa would know where he was and not to worry," Barr said.

Another child asked if he was on the nice list or the naughty list.

"That's a closely guarded secret, and only Santa knows," Barr replied.

HEY, MR. ELF: "Mr. Elf," said one caller, "This is Adam, and I've been really good this year."

BEST OF: Choice questions and comments wound up posted on a flip chart.

"Big sister wanted to add her 3-year-old brother to the naughty list," one read.

"Are there police elves?" said another.

"How much to adopt one of Santa's reindeer?"

CHRISTMAS EVE IN AFGHANISTAN: Five U.S. service personnel answered calls from Afghanistan for about 90 minutes through a conferencing hookup.

"They had a great time," said Novobilski, the program spokeswoman.

NORAD wanted to set up a call center in Afghanistan but that proved too complex, she said.

INTERNATIONAL FLAVOR: NORAD got calls from 220 countries and territories last year, and non-English-speakers called this year as well.

Volunteers who speak other languages get green Santa hats and a placard listing their languages so organizers can find them quickly.

"Need a Spanish speaker!" one organizer called as he rushed out of one of three phone rooms.

FOR GEARHEADS: For people who want to know the specs of Santa's sleigh, NORAD offers a trove of tidbits, including:

Weight at takeoff: 75,000 GD (gumdrops).

Propulsion: 9 RP (reindeer power).

Fuel: Hay, oats and carrots (for reindeer).

Emissions: Classified.