I have yet to see a aircraft gun camera / fire control system of a UFO intercept made by this country released to the public. I have seen some released by foreign governments. If a US fighter engages a target those images exist. The number of intercepts that have happened have to be in the dozens. Classification is the likely reason. FIghter pilots love what they do and some sort of wiki leaks dump to inform the public about UFO's is simply not going to happen for idealism when loss of career and serious jail time is the reward.
The pinning bigfoot cover up on economics interests alone rings too shallow to me. The spotted owl did serious economical impact to the forest industries but it still happened. That could have been buried too if enough money changed hands but that did not happen. If economic factors and powers are that powerful, the spotted owl thing would have been prevented. So if there is an organized government BF cover up, the reason has to go beyond economic factors and power of money. I have a short list of possible cover up reasons. They include: religious implications, revelation of falsification of human history, human/BF hybridization, and extraterrestrial involvement. Might be one or a couple of my reasons or one I have simply not thought of. . Not only do I not want to know the reason but I think it dangerous to get involved investigating it.