To answer the small text in your comment, the reasoning behind why some contrails will persist/spread whereas others won’t can vary; but the most common reason is because the aircraft are at different altitudes.
Other reasons although not usually the root cause is different engines (because they operate at diffferent temperatures) and also if the engines are at different power settings, again for the same reason.
One other thing to consider is that the temperature within ge atmosphere can vary between just a few feet. This can also give rise to how clouds are formed in general and why you can get clouds that are quite literally by themselves in the sky. After all, a contrail is short for a condensation trail, in other words, a cloud.
Edit Sorry didn’t see the other comment above which explains this too but in greater depth! But nevertheless, there are some other reasons which I have highlighted.