The USAF may have seen the SR-71 as a bargaining chip to ensure the survival of other priorities. Also, the SR-71 program's "product", which was operational and strategic intelligence, was not seen by these generals as being very valuable to the USAF. The primary consumers of this intelligence were the CIA, NSA, and DIA. A general misunderstanding of the nature of aerial reconnaissance and a lack of knowledge about the SR-71 in particular (due to its secretive development and operations) was used by detractors to discredit the aircraft, with the assurance given that a replacement was under development. Dick Cheney told the Senate Appropriations Committee that the SR-71 cost $85,000 per hour to operate. Opponents estimated the aircraft's support cost at $400 to $700 million per year, though the cost was actually closer to $300 million.