Love Field staff said that it's possible that smaller general aviation fliers could leave if the airport gets more commercial passenger flights.
Dallas Mayor Laura Miller has also advocated moving some cargo and business jet activity from Love to Dallas Executive Airport, where the city just unveiled a new terminal and other improvements. Executive, in southwest Dallas, faces its share of noise critics as well.
Noise is a complicated issue because so many factors - including humidity, wind and temperature - change how planes sound from the ground.
And people's sensitivities vary.
A jet that flies late at night or during pre-dawn hours may be just as loud as one that flies at noon. But it also may be more annoying. Some Love cargo operators have to fly during pre-dawn hours; Southwest and American stop flying before midnight.
The Federal Aviation Administration considers 65 decibels to be the average noise level incompatible with homes and other development. At Love Field, that's a fairly limited area of 2 square miles - most of which is on airport property.
Southwest's Mr. Kelleher said his airline's flying creates 65 decibels only to Mockingbird Lane. "We are not the problem here," he said.
Peter Kirsch, a Denver-based attorney who represented Grapevine, Euless and Irving in their fight against D/FW Airport in the late 1980s, said the 65-decibel threshold is merely a planning guideline and doesn't reflect how much airport noise exists.
The guideline is an annual average, created by taking measurements throughout the day, under a variety of weather conditions.
"If you put one hand in ice water and one in a flame, you'd technically be at room temperature, but that doesn't reflect the situation," Mr. Kirsch said. "It could mean sometimes there are noise events at 105 decibels, and sometimes there's no noise at all."
Noise levels improving
During the last two decades, the number of people affected by average noise levels above the 65-decibel level dropped to 1 million from 10 million.
"But noise is relative, and as the environment improves, people's expectations increase," he said.
Love Field had one of the nation's earliest noise programs, an effort that marked the birth of the Love Field Citizens Action Committee. The airport has 13 noise monitors and uses them to track airplanes or helicopters that stray from the established - and least intrusive - procedures.
The airport is quieter than it was before 2001 because commercial passenger activity remains down, meaning fewer large jets.
Pat White, co-chair of the Love Field Citizens Action Committee, said noise contour maps don't tell the whole story.
While her home in Bluffview is outside even the 55-decibel zone calculated in 2000 as part of the Love Field Master Plan, "that doesn't mean we don't have impact."
"It's not like it's quiet once you cross over the line," she said.
And while the Master Plan's projections for noise in 2010 show the noise footprint shrinking, that assumes a fleet mix of mostly regional jets, which are much quieter than mainline jets used by Southwest and American.
"If they open up Love Field, the 65[-decibel] area is going to creep much further out, and we can't do anything about it," Ms. White said. "We don't want to move backwards, and that's what would happen."
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