US military pilots sent up to examine the object gave conflicting accounts of what they saw, which is part of the reason the Pentagon has been cautious in describing what the object actually is. Some pilots said the object “interfered with their sensors” on the planes, but not all pilots reported experiencing that.
Some pilots also claimed to have seen no identifiable propulsion on the object, and could not explain how it was staying in the air, despite the object cruising at an altitude of 40,000 feet.