Spend enough time anywhere, and you’re like to see some strange things. Some of us, however, don’t have the pleasure of hanging out regularly in the skies as often as Navy pilots do, and according to some of them, there are strange and unexplainable things up there.

According to the Daily Wire, Navy pilots are speaking up and relaying some of the oddities they’ve witnessed while in the air, including F/A-18 Super Hornet pilot  Lt. Ryan Graves:

Graves said these objects, which appeared between summer 2014 and March 2015, “would be out there all day.”

“Keeping an aircraft in the air requires a significant amount of energy. With the speeds we observed, 12 hours in the air is 11 hours longer than we’d expect,” he added.

Graves and other pilots told the Times that they began noticing strange objects after their decades-old radar system was upgraded. The pilots initially thought they were “false radar tracks.”

“People have seen strange stuff in military aircraft for decades,” Graves told the Times. “We’re doing this very complex mission, to go from 30,000 feet, diving down. It would be a pretty big deal to have something up there.”

Lieutenant Danny Accoin also claimed to have witnessed a strange UFO in the sky, and even got close enough to it for his sensors to lock onto it, with another pilot claiming he almost ran into it:

Another pilot, Lt. Danny Accoin, maneuvered below one of the objects. He told the Times he was close enough to where he should have been able to see it but could not. A few days later, the object re-emerged, and this time a training missile locked onto it. Accoin said his infrared camera locked on, too.

“I knew I had it, I knew it was not a false hit,” he told the Times. But still, “I could not pick it up visually.”

Finally, a pilot saw one of the objects. Graves said the pilot came back from a mission “with a look of shock on his face.”

“I almost hit one of those things,” Graves said the pilot told him. The pilot described the object as “a sphere encasing a cube,” the Times reported.

Footage from these flights showed objects moving in ways no human could survive, such as acceleration to hypersonic speed and then suddenly stopping.

The military recently encouraged pilots to speak up about strange things they see in the sky, and not be hesitant to report them, no matter how odd or unbelievable they sound. While this was primarily to make sure none of our enemies are tossing things over our skies to spy on us or worse, it has come with reports that suggest alien technology may be in our skies.