He thought to himself as he watched it slowly descend, "I guess this must be how people must have felt when they first saw the Titanic."
The Titanic was an era-defining ship. It was large, yet said to be impossible to sink. Many people feigned disbelief when they saw something that large floating in water. He felt that kind of disbelief seeing something this large floating in the air.
He could accept it easily if something this large was floating in the ocean. But he couldn't accept that it was floating in the air because it didn't look like an airplane. It was just a ship. It wasn't an object pretending to be a bird at all.
The ship didn't have propellers. It didn't have any apparent jet engines or rockets. It didn't even have sails.
It didn't look like something that had any business floating in the air. Yet, it was doing so right before his disbelieving eyes.