INDIANAPOLIS -- The Indianapolis Airport Authority plans to auction off thousands of items from its old terminal in an effort to trim an expected $15 million shortfall.

The authority said it hopes to make at least $500,000 as it sells off building materials, office equipment, signs and other items -- such as a 5-foot replica of the Statue of Liberty and 37 posters featuring Princess Diana.

"We don't want to maintain and store items that we're no longer using," said spokeswoman Susan Sullivan.

Airport officials blame the shortfall on a rough economy. The total number of passengers flying out of Indianapolis in April dropped 9.4 percent from the same time last year, while freight numbers are down about 16 percent, 6News' Jennifer Carmack reported.

"We didn't necessarily expect it, but we're not necessarily surprised by it," Sullivan said. "We're adjusting our operations accordingly."

University of Indianapolis finance professor Matt Will said he doesn't believe the airport will have to ask for outside assistance to overcome the financial setback.

"It's not likely that they will go back to the state or the taxpayer and say, 'Help, bail us out,' as was the case with the (Indianapolis Capital Improvement Board)," he said. "I think the funding is on much more sound footing there."

As part of the Aug. 4 auction, industry-specific equipment such as jet bridges will be sold by closed bid, while some building infrastructure will be sold through negotiated sales.

The airport's new $1 billion terminal opened in November.