Try this:
$('.pickupDate').change(function() {
var date2 = $('.pickupDate').datepicker('getDate', '+1d');
date2.setDate(date2.getDate()+1);
$('.dropoffDate').datepicker('setDate', date2);
});
Try this:
$('.pickupDate').change(function() {
var date2 = $('.pickupDate').datepicker('getDate', '+1d');
date2.setDate(date2.getDate()+1);
$('.dropoffDate').datepicker('setDate', date2);
});