Creating a Shipment with the Saturday Delivery Option

UPS

To mark a shipment with Saturday Delivery add the following parameter:

$shipment->setParameter('saturdayDelivery','1');

FedEx

To mark a shipment with Saturday Delivery add the following parameter:

// Ship date matters, for example: You cannot request a Saturday
// delivery on an overnight shipment being picked up on Tuesday.
$shipment->setParameter('shipDate', date('c', strtotime('this friday')));
$shipment->setParameter('saturdayDelivery', 'YES');