Laura O’Brien, defending, said Kowalski had believed the paint could be hosed off the planes.
The defendant herself told jurors she was a Swift fan but “questioned her love” after learning of her regular use of a private jet.
Rebecca Martin added on behalf of Macdonald: “She believed, because she was told, [the paint] wouldn’t have stuck to, stained or corroded the aircraft.
“She believed it would just slide off.”
The judge asked that pre-sentence reports be prepared about the two defendants, warning them “all options” were on the cards for sentencing.