Yes it would. Here is an undetected Iranian drone flying above a US carrier in the Persian Gulf. They didn’t know about it until the Iranians published the photos.
https://www.foxnews.com/us/iran-claims-it-flew-drone-over-us-aircraft-carrier-snapped-photos
How do you know it was undetected?
Probably not any more. That was Jan., 2016. Pretty small stuff can be detected, IF you know what to look for, over wide, flat ground, or open water. But it requires extreme vigilance — probably AI assisted would be best.
In a more complex environment, though, the task is much more difficult. Too much “clutter”. AI can “filter” some of that out. Some.