Recent hikes in the price of the Joint Strike Fighter (JSF), the fifth-generation stealth fighter jet, are holding up the signing of a contract between the Israel Air Force and Lockheed Martin, a senior IDF source told The Jerusalem Post. Last month, the Pentagon acknowledged for the first time that earlier predictions that the plane would cost $50 million-$60 million were inaccurate and that the real cost of the plane would be closer to $100m. Air Force Maj.-Gen. Charles R. Davis, head of the JSF Program in the Pentagon, conceded in a talk at the Brookings Institution that the cost would likely be somewhere between $80m.-$90m. The IDF source, who is familiar with the project and the necessary budget, said the IDF believed the cost would pass the $100m. mark, making it very difficult for Israel to follow through with its initial intention to purchase 75 aircraft. He said that if not for operational considerations, the IDF would have preferred to wait several years and then order the aircraft once the price goes down. In October the Pentagon announced plans to sell Israel up to 75 JSFs. Nine countries - including Britain, Turkey and Australia - are members of the JSF program. Israel enjoys the status of a Security Cooperation Participant after paying $20 million in 2003 to obtain access to information accumulated during the development of the jet. A defense industry source familiar with the negotiations between Israel and the US said the talks were "tough," but predicted that a deal would be reached in the coming months and that Israel would finally place an official order.