There might be something to that. There's been many days when it would be cloudless except for contrails.
There is a correlary to that one; I have observed NOAA photographs of the oceans where the exhaust plumes of ships become a very significant cause for haze over the oceans.
Having circumnavigated the globe on a ship, I can tell you that when we reached the Mediterranean, there never was an end to the haze over the ocean. Only around the equatorial Pacific ocean was it completely gone.