Shows attended by several celebrities went on Sunday. Guests stopped twice on their way to their seats for moments of silence - one for each World Trade Center tower.
Designer Diane von Furstenberg waved American flags on the runway and said her new line is all about renewal.
"I feel like we have to continue. So that's why I call my show, 'Beginnings,' and it's all about hope and I'm feeling very American today," said von Furstenberg.
Several designers said they've made donations to various organizations in memory of the victims of 9/11.
After eight days of spring previews in New York, shows are moving to London, then Milan and Paris.