"I think that extraterrestrial interstellar technology exists"
That is only one possible explanation of what your husband and son observed. It could have been a poorly understood natural phenomenon, a test vehicle of human origin, or instrumentalities of intelligence from another dimension of existence here on Earth. In other words, if there are so-called aliens, it does not automatically follow that they must be extraterrestrial and/or interstellar in origin.
There is no doubt in my mind that we are still at a primitive state in our understanding of physical reality. There are a lot of poorly understood natural phenomena, like homeopathic medicine, applied kinesiology ( I've experienced it working, and am still not sure I believe what I experienced ), and cold fusion. A good web site to explore other strange phenomena is www.sheldrake.org.
I have shared your ideas with my husband. He said, in terms not nearly so diplomatic, that you could take "poorly understood natural phenomenon" and put it where the sun doesn't shine. ;^) He emphasized that what they saw was only two houses away.
I don't mean to sound stuck-up, but this man is very well above average in IQ, has engineering accomplishments that show it, and has always been extremely well-read in technology, aviation in particular. He is a specialist in certain areas of aviation, and makes a living with this knowledge. Certainly the idea of a UFO being a test vehicle of human origin is something he considered automatically. However, this craft moved such an enormous distance so very rapidly, that it was, from his informed point of view, less believable than the extraterrestrial option. As for the possibility that it was the "instrumentalities of intelligence from another dimension of existence here on earth," that seems to me to a more contorted rationale than extraterrestrial options, though I grant you that it's an interesting and real possibility.
There is no doubt in my mind that we are still at a primitive state in our understanding of physical reality. There are a lot of poorly understood natural phenomena, like homeopathic medicine, applied kinesiology ( I've experienced it working, and am still not sure I believe what I experienced )...
Welcome to the club. Experience enough of it (as I have, but that's a whole 'nother talk show) and then hear enough people try to convince you that you've "misinterpreted" your experiences (hmmm .. who does that sound like?) and you will begin to think as I do -- that those people are threatened and insecure, and not genuinely curious about the truth.