The former naval lieutenant said he was worried by the incidents and the Pentagon’s response.
“I am worried, frankly. You know, if these were tactical jets from another country that were hanging out up there, it would be a massive issue,” Mr Graves said.
He said the Pentagon had been unwilling to confront the incidents over US restricted airspace.
“But because it looks slightly different, we’re not willing to actually look at the problem in the face,” Mr Graves said.
“We’re happy to just ignore that these are out there, watching us every day.”
“This is a difficult one to explain,” Mr Graves said.
“You have rotation, you have high altitudes. You have propulsion, right?
“I don’t know. I don’t know what it is, frankly. I would say, you know, the highest probability is it’s a threat observation program.”
Some experts believe the mystery aircraft are advanced reconnaissance drones emanating from Russia or China.
Retired US Navy pilot David Fravor also told the program how he encountered unidentified aerial objects in 2004 off the Californian coast.
He said their lightning speed and handling was superior to his advance FA-18 warplane.
“I don’t know who’s building it, who’s got the technology, who’s got the brains. But there’s, there’s something out there that was better than our airplane.”
In August last year the US Defence Department set up a task force to investigate UFO reports.
The countdown for US military and intelligence agencies to release what they now about UFOs began in the last weeks of the former Trump administration.
When former president Donald Trump signed the $2.9 trillion coronavirus relief and government funding bill into law last December, a small part stipulated the UFO information must be released by June 2021.