Contrails are not 'water droplets'. At -50C or so they very, very, very rapidly become ice particles.
Water droplet clouds, lower and medium levels, are the cause of overwhelmingly the most of the 'greenhouse effect' (CO2, methane, etc. are tiny by comparison).
Ice particle clouds, cirrus, reflect more solar radiation away from the earth than any tiny, tiny (from that high altitude) 'greenhouse effect' that they can have.
Therefore, because contrails are effectively cirrus clouds (and you can often see how they linger to form clear cirrus clouds), they have an overall cooling effect on the earth.
The temperature rise over North America (tiny, but still there) was due to the grounding of all airliners and the lack of contrails.
This last year there was an increase in melting of ice in Greenland because of increased sunshine. Guess what?! There were very, very few airliners on those northerly trans-Atlantic routes that cross Greenland last summer, meaning a loss of all of those cirrus clouds (contrails) and hence more sunshine and more ice melting.
Conclusion? If you are worried about global temperature rises and ice melt, we need more airliners flying!!