Alice Lux and her daughter, Jessica Lux, both of Lewes, Del., wave their Southwest Airlines noise makers April 11 at the gate before boarding a new Southwest Airlines Boeing 737-800 at BWI, en route to Fort Myers, Fla. (Kim Hairston/BALTIMORE SUN)

Bleary-eyed and still clutching their morning coffee, passengers who approached the early flight about to depart Gate A3 found themselves engulfed Wednesday in the hubbub that only airlines really celebrate: A new plane was joining the Southwest Airlines fleet.

But amid the colorful balloons, cheerleader pompoms and general fuss lay the larger story of Baltimore-Washington International Marshall Airport , no longer the stepchild of the region’s three major airports.

The new Southwest jet — a Boeing 737-800 that carries 38 more passengers than earlier 737s — symbolized the growth of an airport that now serves more passengers than Reagan National Airport and might soon surpass the number at Dulles International Airport. Southwest plans to take delivery this year of 33 of the new 737s.

Dulles led the way last year with 23.2 million passengers. BWI served almost 22.4 million, and Reagan National handled 18.8 million.

“It is a very large region, and clearly it can support all three airports,” said Paul J. Wiedefeld, BWI executive director. “Combined, we’re doing over 60 million passengers, so we’re a very large market, just like Atlanta or Dallas. There’s definitely room for all three to grow. We all play to our strength and serve different needs.”

Dulles is the region’s big international airport, Reagan National draws heavily on business travelers, but BWI benefits from its location to draw passengers for all those markets from a broader area.

BWI set a record last year, breaking one set in 2010. And in 2009, BWI and San Francisco were the only airports that experienced growth. If this year continues apace, it will produce another BWI record.

The growth has been spurred by a number of factors. The airport is a major hub for Southwest and the airline it absorbed last year, AirTran, both low-cost carriers whose ticket prices have been appealing to passengers feeling an economic pinch.

BWI also is helped by train service from Washington, Baltimore and Philadelphia and a light-rail system that connects it to Baltimore. It is flanked by two major highways, interstates 95 and 97, and completion of the Intercounty Connector link to I-95 last year boosted access.

“A lot of the growth at BWI is that it’s an easy-come, easy-go airport,” Wiedefeld said. “The ICC made tremendous inroads to the Montgomery and Prince George’s markets. The trip from Gaithersburg to BWI is 35 minutes shorter now.”

It is the airport of choice for labor lawyer Tor Christensen, who has flown from there about 50 times in the past year.

“It’s laid out more conveniently for the business traveler, and the prices for both airfare and parking are much more reasonable,” Christensen said. “Also, the agents there generally are more pleasant to deal with than those at DCA and IAD.”

There’s also the Amtrak connection at BWI. Next week, he said, he plans to fly in from a business meeting in Chicago and hop on a train for another meeting in Philadelphia.

Good for the region

As the growth of Dulles Airport has caused an economic boom along a development corridor, the expansion of BWI has turned it into a regional economic hub and a major financial generator for Anne Arundel County.

Adjacent to Fort Meade, the commercial corridor surrounding BWI long has been home to defense contractors. But more than a decade ago, with the construction of I-97, the 80-square-mile expanse of land that includes the northern part of Anne Arundel and a portion of Baltimore County began to attract high-tech companies and other businesses. The BWI Business Partnership now includes a diverse group of about 175 companies and agencies.

Airport construction began two years after the end of World War II on land where Friendship Methodist Church once stood. By 1957, it was handling 52 departures a day. Now, the average is 344.

Not long ago, the airport completed a major new terminal for Southwest, and construction is about to begin to connect two concourses and allow for 14 new gates, better serving Southwest, which has 194 daily departures this month, and AirTran, which has 44. The merger gave the combined airlines ownership of a third of the region’s air passenger travel.

The acquisition of AirTran gives Southwest new international reach, and Wiedefeld said BWI will benefit as the airline flexes that new muscle.

“It just makes sense that they’re going to begin to expand to other markets,” he said. “If they do, that will put us in a very strong position, given the volume of traffic they have here and the role we play for them.”

A big part of maintaining that role is keeping the per-passenger cost to the airlines low, and BWI’s is just below $10, Wiedefeld said.

“We keep a very, very sharp pencil on that issue,” he said. “We really think through those issues in any decision we make. Reagan is sort of all built out, so their costs aren’t going up all that much because there isn’t that much more they can do there. I would imagine their costs are closer to ours. Dulles is a little different. They’ve put a lot of investment out there, which they needed to do.”

Seeking more revenue

Tara Hamilton, spokeswoman for the Metropolitan Washington Airports Authority, which operates Reagan National and Dulles, said airports are looking hard for additional revenue.

“Airports are looking more and more at non-aviation revenue,” she said. “If we can bring in revenue from concessions, developing land around the airport, charging rent for businesses and parking, then that goes into defraying the cost for operations and that lets you bring down the cost to airlines as well.”

With airlines saddled with soaring fuel costs, the competition caused by low-fare airlines hasn’t cut ticket costs much, but with AirTran and Southwest offering a few flights out of Reagan National and Dulles, some of the legacy carriers have had to match fares on some routes.

Dulles just opened an expanded international terminal intended to speed arriving passengers through.

“We definitely have room to grow, and a prime example is the fourth runway, which we opened a few years ago,” Hamilton said. “Very few airports can do that.”

Christensen, who lives closer to BWI than the other two airports, can fly from any of them, but he prefers BWI.

“I wouldn’t say BWI is my favorite in the country, but it’s my favorite in the region,” he said. “My favorite is San Francisco because of the food. They have the best sushi.”