Thank you.
Contrails, right? Condensation trails.
Si, senora.
And, they appear longer-lasting courtesy of the USEPA.
They have mandated a fuel additive that readily induces the condensation (not silver nitrate, that’s an environmental toxin).
The resulting ice-crystals are smaller and are held aloft for a longer period.
That, plus the ceiling for international flight has been extended higher...where it’s colder and the ice crystals don’t melt as fast.
The mandated additive allows for more extensive upper atmosphere dispersal of particulate matter (PM), a “Criteria Pollutant” defined by the Clean Air Act as a pollutant in need of regulation.