The price tag on the new Salt Lake City International Airport has flown upward by another half-billion dollars and now stands at $4.1 billion.

The Airport Advisory Board discussed reasons behind that on Wednesday, as it also received an update on a new master plan that is looking at long-term needs — even after the new airport is completed.

Officials said the increase comes largely from facilities that have been added or expanded to handle extra growth that has occurred since the new airport was initially planned. That includes such things as a vastly expanded Sky Club requested by Delta Air Lines, bigger areas for customs to handle more international flights and higher tech equipment to speed security screening.

These improvements have been talked about for more than a year as they were incorporated into designs. But their combined budget impact had not been talked about widely.

Bill Wyatt, executive director of the airport, said because of responsibility to bondholders on the project, the increase was first discussed with bond-rating companies in October — prior to the regularly scheduled issuance of bonds for the project.

The Airport Advisory Board was then told, and he said the Salt Lake City Council later approved the increases.

The higher costs will be covered by user fees paid by airlines and their passengers — not through local taxes — and will include some facilities requested by the airlines.

The airport was designed to handle about 10 million passengers a year, but now serves about 26 million annually. The new airport — with a new terminal, two concourses, garage and other facilities — is being built alongside existing facilities without interrupting operations. Its first phase is scheduled to open in September.

At groundbreaking, the first phase was expected to cost $1.8 billion. Other work was added for a second phase that is also underway and includes a long-planned second concourse. That, plus higher-than-expected labor and material costs, had raised the overall price tag to $3.6 billion. The extra additions now bring it up to $4.1 billion.

Also, planners already are looking at long-term needs after the new airport is completed. Those include lengthening one of its major runways to handle larger aircraft expected to fly nonstop to Asia; reworking alignment of taxiways and runways to prevent more delays as operations expand; and obtaining and preserving more land for another runway.

“We’re pretty much concluding the work of the last master plan” by building the new airport, Wyatt said.

Steve Domino, senior planner for RS&H, the consultant working on the master plan for the next 20 years, outlined some of the increases in demand and the problems they may create. For example, in 2017 the airport served 23 million passengers a year. That is now up to 26 million a year. In 20 years, that number is expected to hit 38 million.

In 2017, the airport had 325,000 takeoffs and landings. In 20 years, that is expected to increase to 435,000, Domino said.

(Leah Hogsten | Tribune file photo) A plane takes off at Salt Lake City International Airport on Feb. 24, 2019.

The share of passengers making connections at the airport Is expected to grow from 39% to 47% as Delta is expected to increase its hub operations.

Even with a new airport that is designed to handle far more passengers, “As demand increases, the potential for delay increases as well,” Domino said. He adds the master plan has tried to identify and address potential problems and bottlenecks.

It found one with current designs that often requires aircraft to cut across active runways to reach other runways. With more takeoffs and landings, that may create delays. So planners are adding some “end run” taxiways that cut around the end of runways instead of across them. One proposal would go through a closed airport golf course that some have hoped to reopen.

Also, Delta Air Lines has talked openly about adding nonstop flights from Salt Lake City to a hub in South Korea after the new airport opens. But Domino said research shows that current runways are too short for the largest aircraft that officials likely would hope to use for such flights. The optimal length, he said, would be 14,500 feet long (2.75 miles) — which may require an extension of several thousand feet, depending on which of the three main runways may be expanded.

Also, the major runways now are not exactly parallel — meaning glide paths to or away from them sometimes intersect in ways such that operations on one runway can delay flights on another.

Domino said the master plan is looking at how, when and whether to realign those runways to make their operations more independent to avoid or reduce delays.

The airport also is looking at where it may want to buy or preserve land for future facilities. Domino said more may be needed to the north, south and west. For example, while another runway may not be needed in the next 20 years, one seems likely to be needed in the distant future — and Domino said it may be wise for the airport to protect an area to the west of the airport for that.

“The airport will always be here,” he said. “We need to plan not only for the next 20 years, but beyond,” including allowing that possible runway. He added the airport wants to put off adding that extra runway as long as possible because of challenges it creates with wetlands in the area.