Reading the Wikipedia page about the 1976 Tehran UFO incident, this tidbit caught my attention:
Jafari would eventually retire as a general and participate on 12 November 2007, at a National Press Club conference demanding a worldwide investigation into UFO phenomena.
And do what, exactly?
Let's assume that millions of dollars are spent on a large-scale investigation on the UFO phenomenon and all the reports of alleged UFO sightings and encounters. The end result would be that the majority of cases were either natural (usually weather or other physical) phenomena, optical illusions (the brain interprets incorrectly what it sees) and outright hoaxes. The rest would be unexplained.
Note that "unexplained" does not mean "unexplainable" (ie. not explainable by any of the other mundane possibilities). It simply means that there's no enough data to assess for sure the reason for the report. It's not like we have a time machine we can use to go back to the place and time with more measurement instruments to see what really happened. Without sufficient data it's just not possible to tell for sure what it was. That doesn't mean that it had to be caused by extraterrestrial intelligence.
But let's assume for a moment that some of the phenomena are concluded to be of extraterrestrial origin beyond reasonable doubt. That would be interesting, but then what? What exactly should the course of action then be? What is it, exactly, that these UFO believers are demanding?
Try to make contact with them? If extraterrestrial beings do indeed exist and are visiting Earth, they would have contacted us by now if they wanted to. It's not like they would suddenly answer if we start calling them any more than we already do (think of projects like SETI). If they are not contacting us, there's no reason to think that will change by the revelation that they do indeed exist. Why would it? So what's the point?
Prepare our defenses for a possible extraterrestrial invasion? How exactly? How would this be any different from current military research and arming? What would be different? It's not like we know their technology and would be able to build counter-technology.
What else? This is just a wild goose chase. It makes little sense to spend millions on a project which will give no valuable information.
And this was assuming that there would be a way to confirm beyond reasonable doubt that extraterrestrial beings are visiting us. Well, news-flash: There is no such way. As long as we don't get some concrete physical evidence (eyewitness testimony and photographs not being such) there is no way to determine their existence.
People give way too much credit to eyewitnesses and photographs. The sad truth is that they are unreliable. It doesn't matter how trustworthy and reliable the eyewitness or photographer may be, it still is not enough. It doesn't matter if a commision of the presidents of the largest countries in the world, alongside with Stephen Hawking, Neil deGrasse Tyson and James Randi were videoed and photographed shaking the hand of an extraterrestrial in front of his landed spaceship, and they were personally interviewed and gave their word of honor that the event was completely real and accurate, it would still not be proof enough.
If the alien gave abundant blood/tissue samples and extraterrestrial technology for any independent research teams from different parts of the world to study, and numerous serious peer reviewed papers were published on reputable scientific journals about this subject, and the general consensus of the scientific community was therefore that the event was real, then we might be talking business. Not a moment sooner. Eyewitness testimony alone would not be enough, no matter how reputable the eyewitnesses. Most UFO believers just can't grasp this concept, no matter how much it's repeated to them.