Indeed. This is as much a menace to astronomers as light pollution. There's a global aspect to contrails as well, persistent contrails increase global warming by reflecting more heat back to ground than the reduction in incoming radiation. We should be campaigning to have aircraft fly at heights where they do not leave persistent contrails; this would increase aviation fuel consumption by approx. 5% but reduce the global climate impact of the aviation industry by a factor about 5 to 10.