NEW HAVEN — Efforts to revive Connecticut’s economy must include solutions for the problems facing its cities, the mayors of Hartford and New Haven told members of the state’s Commission on Fiscal Stability and Economic Growth.

Hartford Mayor Luke Bronin and his New Haven counterpart Toni Harp said the rules that govern what types of properties are not taxable work against the best interests of the state’s cities.

“We have built our cities on a base that is too small to allow them to be competitive,” Bronin told the panel. “Each of our cities have a large amount of untaxable property.”

One of the primary attempts to level the playing field when dealing with communities that have large amounts of tax-exempt property is to provide payments in lieu of taxes, he said. But Bronin added that the way payments in lieu of taxes are structured “is flawed because such programs are often underfunded” and have different levels of payments for different types of property.

Harp said the current system of state aid to cities “is simply unsustainable.”

“State government restricts the ability of local governments to generate revenue,” she said. “In Connecticut cities, with their concentration of colleges and universities, hospitals, state, federal, and religious buildings, and other not-for-profit properties, the resulting gap between revenue and expenses is daunting — and worse.”

New Haven and the state’s other major cities take on regional responsibilities and costs that surrounding suburban communities benefit from, Harp said.

“In Connecticut, there isn’t the benefit of a county level of government, so cities are relied upon to host - and bear the cost of — a broad range of regional services,” she said. “The job of this commission, as I see it, is to safeguard the fiscal viability of Connecticut cities so they remain the economic engines the rest of the state requires - and relies upon.”

In addition to the important role that cities play in driving the state’s economy, improving transportation is also critical to that effort.

Tweed New Haven Airport Authority Executive Director Tim Larson said the airport, which straddles the city’s border with East Haven, could increase its passenger base from the current level of 28,000 to 250,000 if the transportation facility’s runway were to be extended to 6,000 feet. Even operating at its current capacity, Larson said Tweed generates $55 million in economic value to the region.

Kevin Dillon, executive director of the Connecticut Airport Authority, said Bradley International Airport in Windsor Locks served 6.5 million passengers in 2017 and “could easily handle 10 million with a few improvements.”

“Every international passenger we bring in adds $1,700 to our economy,” Dillon said, justifying incentives paid to Irish airline Aer Lingus to fly out of Bradley.

The airport is in the midst of a construction project that will bring all of the airport’s car rental operators together in a hub just steps away from the main terminal building, he said.

Dillon said efforts to expand Tweed and Bradley can co-exist.

“There is room for two airports in this state, but at the same time, we don’t want to see Tweed competing with Bradley for resources and vice versa,” Dillon said.

The commission is expected to release its recommendations by the first week in March, with the timetable for the release of the recommendations designed to give the Connecticut General Assembly time to implement some of the group’s proposals for fixing the state’s economic woes.