Thanksgiving Day parades are now as much a holiday tradition in America as turkey and cranberries, and for 15 years, Bob Kemp has been behind the grandest part of the most famous parades in the country.

Kemp makes those huge Popeye, Woody Woodpecker and Yogi Bear float balloons that glide down parade routes and in football stadiums across the nation today. And from his warehouse in Glen Burnie in Anne Arundel County, Kemp also has produced an 80-foot-high alligator and a 67-foot Felix the Cat that have made appearances at the Kentucky Derby, the Indy 500 or the Cherry Blossom Parade.

"It's a fun business," Kemp said, "although I can't remember the last time the family all spent Thanksgiving together. '72?"

Kemp, 56, was director of tourism for the City of Baltimore before he began this business, which he said brings in more than a half million dollars a year. He was organizing the Preakness Week Festival to celebrate the famous horse race when he decided to build his own floats. His work was noticed by scouts from Gimbels department store in New York, and in 1971, they commissioned 10 balloons from him for their parade.

"I didn't know anything about making balloons," Kemp remembered with a laugh, "but I had a contract."

Since then, Kemp Balloons Inc. has made many of the nation's best-known "character" balloons, among them the Kool-Aid man, Olive Oyl, and his first character, a 55-foot Pillsbury Doughboy.

"The first time I worked for Macy's {which still uses three of Kemp's balloons in its Thanksgiving Day parade} I said, 'Look, you better hire me now while I'm cheap, because after this I'm going to be expensive,' " Kemp said.

Indeed, Kemp's work is so well known that he can command $15,000 to $100,000 to provide balloons for a parade, although balloons can be rented for $500 to $11,000.

In 1976, Kemp produced the only balloon ever to be used in a presidential inaugural parade. Because the man being sworn in was Jimmy Carter, the balloon was, appropriately enough, a giant peanut.

Goodyear had turned down the commission, but Kemp's son, Bob Jr., designed the 30-foot peanut, which took 12 days to build.

Kemp and another son, Russell, a technician for the company, call Bob Jr. "a genius," and credit him with being the driving force behind the company.

Together, the family has produced 70 balloons in the 12,000 square feet of its warehouse.

Kemp has anywhere from eight to 25 people working for him at one time, some of whom are art students getting part-time work.

The balloons are made of nylon and coated with a specially processed pigmented rubber, "the same as the Goodyear blimp," Kemp pointed out.

After the balloons are designed, they are cut along a specific pattern.

They are filled with helium and cannot expand past the material allotted for them without blowing up.

If they have a leak, a technician has to crawl inside to find the hole by looking for spots of light.

And the balloons cannot be repainted too many times, Kemp explained, "because if you put too much paint on them, they get too hard to fly."

It's not easy getting the balloons to fly in any event. Kemp said he was the first person to make an upright balloon with his Pillsbury Doughboy; before that, parades used "ground balloons," which were flown low enough to the ground to avoid obstacles such as telephone lines.

Kemp realized that all he had to do was tip the balloon over to clear the lines. He said this still produces a loud "oooh" from the crowd, as the balloon looks as if it is about to fall down, and an "ahhh" as it emerges unscathed on the other side of the wire.

"In some places, like Miami, we are up and down, up and down, the whole parade," Kemp said.

In Atlanta, Kemp lost a clown balloon that was tethered to the top of a motel when a cold front blew in. Although rewards were offered for its return, the balloon was never recovered.

At the time, Kemp said he thought, "Can you imagine a plane flying up there and seeing this thing going by?"

And in San Antonio this year, the Kemps made a 100-foot cloud that was to have served as a background for Pope John Paul II as he spoke from a platform during his visit in the fall.

Days before the event, foul weather struck the area and the cloud crashed to the ground.

The Kemps spent 18 days repairing the cloud, but at the last minute nervous organizers decided not to let it fly.

Today Kemp is scheduled to be in Philadelphia with his 65-foot Popeye, which has been inflated with 22 tanks of helium. The balloons are all deflated for travel, although without the helium they can still weigh as much as 50 pounds.

Russell is in Santa Ana, Calif., and the rest of the workers are scattered in Houston, Green Bay, Wis., and Richmond.

"We do little parades in Kalamazoo and big parades in New York," said Kemp, who has another reason for being proud of his work. Kemp grew up in the Glen Burnie and Baltimore area, and has remained in Glen Burnie even though he now has a nationwide business.

"There were people here who thought I was never going to amount to anything, and I wanted to show them," he said.

And as millions of people flick on their television sets today to watch Thanksgiving Day parades and football games, he is going to show them too.