WHEN John King goes aloft in his hot-air balloon, he has only a vague idea of where he will land. "It goes with the wind," the United Airlines pilot said. "It's a massive piece of equipment. It's like a giant spinnaker and it's moving rapidly."

This weekend, King and more than 20 other balloonists from Virginia, Maryland, Pennsylvania and New Jersey will launch their propane-fueled balloons at the 26th annual Hot-Air Balloon Festival at the Flying Circus Air Show in Bealeton, Va. And if all goes well, the balloonists will rise into the air and begin moving quietly through the sky, aiming, they hope, for a pole at the Flying Circus's airfield that holds a prize. The balloonists, King said, will try to grab the prize. "It's difficult; we've given the prize away only once in 25 years."

The hot-air balloon launches will take place between 6:30 and 7 a.m. and again around 5 or so in the afternoon both Saturday and Sunday. The wide spread in times is forced by winds, or rather the lack of them, said King, who organizes the Hot-Air Balloon Festival. "During the early morning hours the winds are typically calm," he said, "and during the last few hours prior to sunset we also look for calm winds." After the balloon show, the Flying Circus offers rides in small planes and even open-cockpit biplanes for $20 and up. Visitors can also take a short ride in a tethered hot-air balloon for $5. (Some hot-air balloonists may take passengers on the morning and evening launches, with the price to be negotiated with each balloonist.) The balloon and airplane rides are offered again after the air show.

From 2:30 to 4:30 both days, the Flying Circus Air Show is presented, featuring parachute jumping, formation flying, comedy and acrobatic stunts and even wing-walkers.

Asked where the Flying Circus finds wing-walkers, King said they advertised for them: "Wingwalkers Wanted. No Experience Necessary. Will Train."

"Twenty to 30 people showed up," he said.

King, a 52-year-old pilot of a Boeing 767, admits that he and his son are also wing-walkers. "My son [29-year-old John E. King II] grew up around it. My dad and sister had done it years ago. It was the thing he wanted to do. The main wing-walkers in the air show are Kurt and Jane Wicker."

Asked whether he tells his United passengers that they are flying with a wing-walking pilot, he admitted, "I usually don't mention it."

HOT-AIR BALLOON FESTIVAL -- Hosted by the Flying Circus Air Show on Saturday and Sunday. Balloon launches begin at 6:30 a.m. and around 5 p.m., weather permitting. The All-American Barnstorming Air Show is from 2:30 to 4:30 each day. Admission is $12, $3 children ages 3 through 12 (younger free). Take I-66 west to U.S. 29 south to Warrenton, turn south on Route 17 and then left on Route 644 to the Flying Circus Aerodrome in Bealeton, Va. Call 540/439-8661.