The only way to stop them is to ban airplanes. I don't think that plan will go over well with the public. But Greta will love you for it, I'm sure.

The best way to prevent them (other than just not flying) is to fly at lower altitudes. But that uses much more fuel than flying at higher altitudes with thinner air. So airlines would either have to sacrifice their profits and enrage their shareholders or they would have to hike their fares up around 60% more than what they are now, according to what I've read about it.

And that just reduces the number of trails. It doesn't stop them all.

The only way to stop them is to ban airplanes. I don't think that plan will go over well with the public. But Greta will love you for it, I'm sure.