The 200% mileage match is good for both the base and bonus miles. For example, if you had a 2 day rental at Alamo with this promo, you would earn 100 base miles + 200 bonus miles = 300 miles. NW would throw in 600 additional miles. Therefore, you would earn a total of 900 miles, 600 of which would count toward elite status (we refer to these as "credited flight miles").

Even if you aren't an Elite member, this is still a great offer because the 900 miles are good toward free award travel.