US cruise missiles for one.
As I understand it, cruise missiles in their cruise mode actually function with a jet engine, and therefore have no rocket plume. Some cruise missiles are launched with rockets, but this takes seconds, not minutes.
We do not know what type of missile it was
Since the exact same phenomenon was seen at the exact same time the following day, and at the exact time that a known passenger flight was coming in from the Pacific, we know for certain that it was not a missile.
Not the exact same phenomenon. That is covered later in the thread. No one is stating that aircraft plumes do not look like rocket plumes. They can. The question is whether this specific plume was rocket or aircraft. Now if you admit that they can look similar, you admit it could be a rocket.