I think as much as 20 percent of airport revenue will eventually come from retail.

Mr. Gulia said that using airport revenues to pay for airport improvements follows Federal guidelines.

In any event, the town looks forward to the airport revenue that would be generated by commercial traffic.

In response, critics of the larger terminal argue that reliance on airport revenues to finance the improvements would lead to the expansion they fear.

Mr. Doughty said the new airport can still be built entirely from airport revenue and without any additional taxes.

VIP ground services already exist, but a substantial increase in users has justified expanding the facilities, which will also boost airport revenues.

Bangor International is operated as an "enterprise fund", which means that the expense of operating it comes from airport revenue.

All airport revenue is generated through rental and other user fees charged to patrons and tenants of the facility.

But the Port Authority has an exemption that allows it to use airport revenues to pay rent to the city.

The cost, $150,000 a month, will come out of airport revenues and will eventually be paid by travelers through airport charges, he said.