Some days, it's hard to see much improvement at Worcester Regional Airport. Blame the fog.
Since taking over the airport in 2010, the Massachusetts Port Authority has spent millions of dollars to spruce up the ailing facility's terminal and runways. It even convinced JetBlue Airways to last month become the first major carrier to fly out of the city in a decade, with two round-trip flights a day to Florida.
But for all that is new, the fog remains the same, keeping a lot of planes on the ground.
In the airline's first month of Worcester service, JetBlue canceled 15 flights and diverted five planes to Boston's Logan International Airport — nearly 15 percent of 136 scheduled arrivals and departures — mostly because of the blanket of fog that often envelops the hilltop airport. The groundings forced about 1,400 passengers to scramble to rearrange their plans. By comparison, JetBlue canceled less than 1 percent of its flights out of Boston during that period.
Massport plans to install a $32 million instrument landing system and parallel taxiway that will allow planes to touch down in almost zero visibility, but those will not be in place for several years. In the meantime, the soupy murk is already straining JetBlue's long-awaited new service.
Some Central Massachusetts residents, like Brad Wyatt, are starting to wonder whether Worcester is worth it.
The night before his family's Dec. 3 flight to Orlando — a birthday trip to Disney World for Wyatt's 10-year-old daughter — the airline called to say the plane had been diverted to Boston due to fog.
Instead of conveniently boarding a plane in "The City of Seven Hills," though, the family took a bus 50 miles east to Logan.
"It makes me think to myself, 'Do I really want to book my flight out of Worcester next winter?' " said Wyatt, who received several $100 travel vouchers from the airline for his trouble.
Many blame the plight of Worcester's airport on its unfortunate geography. Not only is it far from a major highway — requiring a 5-mile drive along residential roads — and located within an hour of four larger airports that siphon off potential passengers, it is 1,000 feet above sea level.
While that elevation is not exactly nosebleed high, it's 400 feet above the city proper, so when relatively warm, moist air flows in from the ocean and makes that sharp climb, the temperature drops quickly and creates clouds, meteorologists say.
According to JetBlue's own meteorologists, Worcester has fog about four times as often as Boston, 42 more days a year.
JetBlue pilots can only land planes in Worcester when visibility is at least three-quarters of a mile, but fog often reduces it to less than a half-mile.
On top of that, Worcester also gets a lot of snow — nearly 109 inches last year, compared with just over 42 in Boston, so winter means added challenges. "It's a pretty foggy and snowy location," said Mark Paquette, a meteorologist at AccuWeather and a native of Leicester, just down the road from Worcester. "Both of those weather factors are not good for flying."
Worcester has long struggled to maintain airline service. In 2001, the airport had four network carriers, but by 2003, they were all gone. When Direct Air started flying out of Worcester in 2008, it was the first regular service in two years.
The new instrument landing system should help alleviate one of the major obstacles to maintaining service, using radio transmissions, GPS technology, and new lighting to help guide planes in even when the airport is mired in the mist.
"The bottom line is we are an airport that operates out of the Northeast, and we are prone to the weather just like other airports," said Andy Davis, Massport's Worcester airport director.
Indeed, several area airports have struggled with cancellations this month. Airports in Burlington, Vt., and Bangor have axed about 10 percent of their December flights, according to the Texas data services company FlightAware, while Worcester has dropped nearly 14 percent.
JetBlue said that despite the weather problems, it remains confident in the Worcester service.
The two daily round-trip flights, to Orlando and Fort Lauderdale, have consistently been more than 70 percent full. That's "a very quick ramp-up for a new city," said JetBlue spokesman Bryan Baldwin, who noted that JetBlue conducted an in-depth analysis before committing to Worcester.
Currently, the airport is on track to serve about 100,000 passengers a year. If JetBlue adds more flights, as planned, seven daily roundtrips could attract a half-million people a year within 10 years, according to a study commissioned by Massport.
"We knew that there were operational challenges that we were going to face, but we felt that the benefits outweigh those," Baldwin said. "We want to figure this out."
Canceled flights wreak havoc on an airline's schedule, as well as its finances, said Daniel Kasper, an aviation consultant at Compass Lexecon in Boston. Kasper noted that Worcester's fog is usually worse in the winter, when demand for service to Florida is strong. With several more reliable airports close by, he said, vacationers might start booking their flights elsewhere.
"People say, 'Gee, I'd like to fly out of Worcester, but I can't take the chance,' " Kasper said. "That level of cancellations, that's hard to sustain."