I haven't had any encounters with aliens, but my mom has.
On 9/11/2001, Yes, I'm serious, my mom went on a walk on the waterway after watching the news for hours.
This was in the evening time, so the No commercial flights sanction was already in place.
While on her walk, she looked up after feeling like someone or something was watching her, and she saw a triangular craft floating above her.
At first she thought it might have been a military craft of some sort, but then realized it was making absolutely no noise.
She said it was so low to the ground that she probably could have touched it if she wanted to, but before she could reach out and touch it, the craft zipped away quickly with no sound at all.