The question of whether intelligent alien life is visiting us here on Earth – and whether the government is covering it up – is no longer a topic reserved solely for conspiracy theorists to debate.

Congressional leaders continue to pay serious heed to the possibility that not only are unexplained objects violating U.S. airspace, but that the military has spent decades covertly recovering the craft to bolster its own technology.

On Wednesday, a new slate of witnesses provided fresh testimony on precisely these concerns during a joint hearing by subcommittees of the House Oversight Committee. The hearing, which surpassed two hours, represented Congress' latest foray into the topic of UFOs following another round of testimony in July 2023.

The hearing's title? “Unidentified Anomalous Phenomena: Exposing the Truth.”

The UAP acronym is the official term the government now uses to refer to the unexplained phenomena, arguing it is less loaded and stigmatized than "UFO," but it also accounts for the fact that, as witnesses reinforced on Wednesday, many sightings are of objects in the water.

Legislators have spent the past year pushing for new laws that would boost UAP transparency, with one seeking to create a civilian reporting mechanism, and one directing the executive branch to declassify certain records. But elected officials and UAP transparency advocates say it's not enough.

Congress is revisiting UFOs:Here's what's happened since last hearing on extraterrestrials

In her opening remarks, Nancy Mace (R-South Carolina) laid out just why another hearing was needed: to call upon transparency from the executive branch and intelligence agencies that have long been guarded about classified UFO information.

Of the Department of Defense and its Pentagon headquarters, Mace said the organization's reputation for secrecy is "not a track record that instills trust" among the public.

"The reality is, despite their enormous taxpayer-funded budget, the transparency of the defense department and the intelligence community have long been abysmal," Mace said.

Glenn Grothman (R-Wisconsin), whose subcommittee held the hearing along with Mace's, had this to add: "We cannot shy away from the unknown when the stakes are so high."

Here's a look at some of the most compelling testimony that each of the four witnesses provided:

Email about UAP wiped from account, retired Navy rear admiral says

Timothy Gallaudet, an American oceanographer, described an email he received in 2015 during training exercise taking place off the East Coast when he was serving as the U.S. Navy's chief meteorologist.

The email warned about "multiple near-midair collisions" and attached a now-declassified video of a UAP captured by a Navy F/A-18 aircraft.

Gallaudet, retired rear admiral in the U.S. Navy, testified it was clear that the intent of the email was to ask if anyone was aware of classified technology demonstrations taking place. But the next day, he said, the email appeared to be wiped from his account.

Gallaudet described a disinformation campaign amongst high levels of the government, including the Pentagon's office to investigate UFOs, to discredit reports and the whistleblowers who make them.

Gallaudet also testified about satellite imagery of UAP captured in 2017 that has not yet been shared with Congress. He declined to divulge where the image was taken, but, when questioned, described it as a "disc-shaped object."

Pressed about what he thinks the objects that have been observed could be, Gallaudet said "nonhuman higher intelligence."

Elizondo: 'We are not alone in the cosmos'

When former Pentagon intelligence official David Grusch testified in 2023, what he had to say under oath set off a firestorm.

Among Grusch's claims, offered without evidence, were of an alleged shadowy "multi-decade" Pentagon program to retrieve and study not only downed spacecraft, but extraterrestrial pilots. Grusch also accused the Pentagon under oath of being aware of extraterrestrial activity since the 1930s and hiding the program from Congress while misappropriating funds to operate it.

Though congressional leaders said they have not substantiated those claims, one witness Wednesday did corroborate much of what Grusch said.

Luis Elizondo, a former military intelligence official who resigned and went public in October 2017 after 10 years of running a Pentagon program to investigate UFO sightings, still made it clear he was constrained in much of what he could say.

In his opening remarks, Elizondo lambasted the intelligence community for its decades of "excessive secrecy" around UAP reports "all to hide the fact that we are not alone in the cosmos."

"I believe we as Americans can handle the truth and I also believe the world deserves the truth," he said.

Much of Elizondo's concerns relate to national security, resting on the fact that much of the reported UAP activity has been around military bases and nuclear weapons sites.

"If this was an adversarial technology, this would be an intelligence failure eclipsing that of 9/11 by an order of magnitude," he said, adding that, as Grusch claimed, many of the government's UAP programs operate without proper congressional oversight.

And as many have testified before, Elizondo reiterated that the objects observed have often out-maneuvered U.S. military aircraft and were flying in a way beyond the capabilities of known human technology. In fact, he alluded to one secure email he observed that used the word "stalked."

Witness: Gov. sitting on trove of UAP imagery

One of the more compelling revelations was a report shared by journalist Michael Shellenberger about a secretive UAP program created in 2017 following a New York Times story exposing another top-secret Pentagon program.

Intelligence communities "are sitting on a huge amount of visual and other information" about UAP," Shellenberger testified, "and they have for a very long time and it's not those fuzzy photos and videos we've been given, it's very clear, high resolution."

Asked how many images or videos, Shellenberger said "hundreds, maybe thousands."

NASA called upon to invest in UAP research

While NASA released its own UAP report last September, Michael Gold, a former administrator at the space agency, called on the organization to do more.

NASA's investment into UAP research "would make a powerful statement to the scientific community that UAP should be taken seriously," Gold, who is part of an independent NASA UAP study team, testified.

While many UAP can often be explained as drones or weather events, Gold advocated for NASA to invest in instrument tailored to study the phenomena, which was among the recommendations in its report.

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at [email protected]