vertical and horizontal flares moving slowly in the sky

I saw a bright vertical streak of light high in the sky. When I went out into the backyard to get a better look I noticed there was another one but it was perfectly horizontal. As the horizontal one moved slowly to the left (south), the vertical one descended slowly toward the treetops until they both faded away. The horizontal one was probably 3 times as long as the vertical one. There may be a perfectly good explanation for this but I sure don't know what it is. I read that iridium flares only last for a few seconds, and this lasted for about 5 minutes so I ruled that out. If you have any ideas I would really appreciate an explanation. I did get a couple of pictures of the vertical one. I am sending them to you. Thanks!
Both photos are of contrails against a clear sky.  PD