I never thought it about as a green house thing before though I do remember reading an article many years ago that contrails do contribute when they spread out into cirrostratus clouds.

I was a meteorologist in the Air Force and did make forecasts telling pilots at what levels to fly to avoid making contrails since having a long silver line pointing to your exact location makes sneak attacks a little difficult. Perhaps commercial airlines should make use of that information. It’s usually just a few thousand foot difference. Fly a little higher or lower and problem solved.