Two weeks after the U.S. shot down a Chinese spy balloon and one week after President Biden directed the military to shoot down three more unidentified objects, America is still gripped by questions over what the objects were and why they were flying at a height that posed a risk to air traffic.

President Biden on Thursday delivered his most extensive remarks to date on the situation, in which he all but ruled out that the three unidentified objects were part of the Chinese balloon program or that they were a foreign intelligence-gathering effort.

But with officials still unable to collect the debris from the latest downed objects, there is still much more to be learned about to whom, what their purpose was and how they ended up in a position to be shot down.

Who owns the objects?

Biden backed the intelligence assessment from his National Security Council that the unidentified flying objects (UFOs) were “most likely” related to a private company or research institution, but did not go further to explain the conclusion.

The North American Aerospace Defense Command (NORAD) was able to detect the UFOs after tuning its radars to scan for the objects, which were flying at an elevation of 40,000 feet or below and posed a threat to civilian aviation.

Guy Gratton, an associate professor of aviation and the environment at the United Kingdom’s Cranfield University, said hundreds of weather balloons go up across the world every day.

But it would be “irresponsible” to send them up to around 40,000 feet, where they can interfere with air traffic, Gratton explained.