It used to be that the government was trying to discourage reports. They would explain away everything that did get reported--usually reasonably because most sighting were just ordinary things that were misidentified but there were some that they never publicly had good explanations for.
They encouraged treating people who said they saw UFOs as kooks, and were successful enough that when pilots saw something they could not explain they would usually not report it because that could affect their career.
Lately that has flipped. Now they want reports.
The explanation that best fits the facts is that in the past what the people who weren't just misidentifying some normal thing were seeing were secret government projects that had accidentally been flown where they should not have been.
The government didn't want people to talk about those sightings because if too many people did talk about them it might be possible to piece together details about the program.
Now there are some sightings that don't fit with misidentification of normal things and that the government can't match up with any of their secret projects and they want to know what the heck is going on. They almost certainly don't think it could be extraterrestrials--foreign spies is what they are probably worried about.
They need more data, and so now they want people who see things to report it.