For seven months, Independence Air existed only in TV and radio spots featuring the likes of James Carville, in newspaper ads trumpeting "lower than low" fares, and inside Washington's Dulles International Airport, where employees were taught a new way of running an airline.

Yesterday, the airline took its boldest step yet. It flew.

Independence Air Flight 1995 pushed back from Dulles's Gate 2A at 6:29 a.m. -- one minute ahead of schedule -- bound for Atlanta.

And an airline was born -- actually, reinvented -- amid skepticism from industry analysts, preemptive strikes by competitors and enthusiastic reviews from customers delighted to get a bargain.

Independence scheduled 78 flights yesterday to and from Boston, Newark, Atlanta, Raleigh-Durham, Chicago O'Hare and Dulles, which the airline predicts will become the nation's largest low-fare hub. Most of the people walking off planes seemed to be leisure travelers, many with backpacks, who chose Independence over buses and trains.

"This was almost as cheap as riding the Greyhound," said Yevgeny Grigoryev, 21, a student at Methodist College in Fayetteville, N.C. He said he was paying about $100 to travel on Independence from Raleigh-Durham to Dulles to Newark.

Grigoryev was on his way home to Russia, trying to do things on the cheap. "With fares like this, I'm going to fly Independence Air again," he said in the midst of a cake-and-champagne party the airline was throwing for itself in Dulles's Terminal A. A swing jazz band played "Sentimental Journey."

Independence officials declined to say how many seats they sold for yesterday's flights. Passengers stepping off several newly painted and refurbished 50-seat jets said their flights weren't full. One afternoon flight from Dulles to Boston was almost full, but some passengers were non-paying airline employees.

Independence Air is actually a new face on 15-year-old Atlantic Coast Airlines Holdings Inc., which operated regional feeder jets for United Airlines and Delta Air Lines. When United filed for bankruptcy and tried to reduce the amount it paid Atlantic Coast to operate the feeder flights, Atlantic Coast elected to go its own way. As a regional carrier, Atlantic Coast had flown airplanes but left the marketing, reservations and customer service to United and Delta.

By fall, Independence plans to offer 700 daily systemwide departures to at least 50 destinations.

"They're transforming their entire business within a space of a few months, and that is a tremendous challenge. And there are lots of questions," Robert N. Ashcroft, an analyst with UBS Investment Research, said yesterday. "Can they manage a hub with 87 airplanes? They have never done that before. Can they manage customer service for that many people all at once? Forget about doing it profitably. Can they just do it?"

Analysts are also concerned that reservations for Independence can be made only through the airline's Web site or toll-free phone number. Independence, concerned about costs, decided not to pay to be listed on the widely used Orbitz, Travelocity or Expedia Web sites.

"The one thing we have going for us in the D.C. marketplace is there are more Internet users in the D.C. area than in any city in the U.S.," chief executive Kerry Skeen said.

Skeen said he'd rather spend the company's money on advertising and community sponsorships. Last weekend, for example, Independence was a sponsor of the District's gay, lesbian, bisexual and transgender festival. And he hired political consultants Carville and his wife, Mary Matalin, as well as comedian Dennis Miller, soccer star Mia Hamm and musician Chuck Berry for its pitches.

Sadie Johnstone, 24, a medical student from Arlington, booked an Independence flight from Boston to Dulles online after seeing one of the TV ads at her health club. She paid $59 one way, plus tax.

"I hope this starts an airfare war," she said with a laugh.

Some customers got a jolt -- then a laugh -- when the preflight safety announcements were delivered by the celebrity endorsers.

Rock-and-roller Berry said in his announcement, which was approved by regulators, "In the extremely unlikely event that the aircraft lands in water, the seat cushion will keep you afloat. Just pull up on the front, put your arms in the strap and hug it as tight as you hug your baby on a Saturday night . . ."

There were a few opening-day glitches. A brochure showing cities the airline will eventually serve listed Greensboro, N.C., as Greensboro, N.Y., for example. And the airline briefly ran out of forks for cake at the party.

Flight 1134 from Boston to Dulles was delayed for about three hours; passengers were told it was because of bad weather at Dulles. For an hour and a half, as the plane sat on the tarmac in Boston, flight attendants passed out drinks and snacks and tried to entertain passengers with guessing games, until Capt. David Wojtanowski decided to take the plane back to the gate. Once inside the airport, airline workers ordered pizza for the passengers.

Everywhere there seemed to be the specter of competition. "Boooooo," some Independence employees yelled when they spotted a Ted jet, operated by United, taxiing onto the runway at Dulles.

Or, as Flight 1134 passenger Jeff Leiter, of Great Falls, Va., described his predicament: "If you believe in conspiracy theories, then maybe United and US Airways conspired to arrange this."

Staff writer Keith L. Alexander contributed to this report.

Independence Air employees clustered just outside the gate area at Dulles to watch Flight 1187 leave for Boston.