Am I correct in my understanding of what you are saying?

You are convinced that spacecraft which have been constructed by extraterrestrials can not exist.

That may sound like a stupid question, specifically after reading your post, but there is a reason why I want to be sure of what you are convinced of at this moment in time.

People often change their mind about personal convictions.
I’m very curious about the process of why a person would change their mind.

I know that neither you or I can change another persons convictions, but since we are intelligent beings we should be able to discuss in detail the reasons why we believe something to be true.

I’d like to know, if we deduct the “spacecraft” and “distance” out of the extraterrestrial equation, are you still saying that no intelligent life can exist anywhere else in the universe?

Have you ever considered that there might be extraterrestrial artefacts somewhere but they have not been adequately examined or published?

Is there a reason why the information from these meteorite cameras is being suppressed?
http://www.habitablezone.com/space/messages/552551.html

You are right that when something moves fast enough through the air it causes a sonic boom, but those items that exhibit such behaviour are either meteorites or airplanes and both of those articles push the air in front of them
Have you ever wondered what would happen if the object was not pushed but rather pulled through the atmosphere?

What would happen if the air in front of the craft was diverted to the rear of the craft very smoothly, would there still be a sonic boom?