Northwest WorldPerks members can now earn 50 miles in each direction when booking airport rides on SuperShuttle via www.supershuttle.com. SuperShuttle offers shared van rides to and from your home, office or hotel and any of the 27 airports in 22 cities served by the service in the United States. Members will earn 150 miles each direction for ExecuCar rides booked at www.execucar.com. ExecuCar is a luxury sedan service owned and operated by SuperShuttle that is available in 11 cities across the country.