Which term correctly identifies the short and long trails left by planes and jets?

My father was an engineer for Pratt & Whitney Aircraft for over 30 years. At one time he oversaw the jet engines at Westover AFB in Massachusetts. At that time - in the '60s & '70s - they were called vapor trails and only produced by military aircraft because they were the only ones to fly high enough to produce them.

Player #41747600, That's what a United Airlines pilot friend told me too.

somehow got it right!!