Are we being visited by extraterrestrials or interdimensionals?

When a UFO is spotted, do you think it's more likely to be an extraterrestrial or an interdimensional craft?

I'm assuming extraterrestrial means from another planet and interdimensional means from another dimension, but I don't really understand the concept of someone visiting from another dimension. Does that mean they get here through a portal? Where in the universe might they be coming from? Do they have a home planet?

I guess I'm looking for someone to explain the concept of interdimensional travel. I don't really get it lol. Extraterrestrials coming from another planet makes sense, but I don't really understand coming from another dimension. How does that really work?

As a bonus topic to discuss, do you think the TicTac UFO from the USS Nimitz incident was an extraterrestrial craft or an interdimensional craft?