United Airlines Mileage Plus members can earn 1,500 bonus miles when booking a car with Hertz.
The promotion is available when booking and collecting a mid-size or larger car through united.com before October 31.
Members must quote discount code (CDP) 62455, PC#305023 and their Mileage Plus number at the time of reservation.
Standard Mileage Plus members normally earn 500 miles per booking; Mileage Plus Chase credit card holders earn 750 miles; Mileage Plus Premier Gold and Premier Silver members earn 1,000 miles; and Mileage Plus Global Services, Premier 1K and Premier Platinum members earn 1,250 miles.
United named Hertz as its preferred car rental partner last year (see news, October 2014).