Biz cardholders can now earn double miles. Comerica recently announced it will award double miles on its suite of commercial cards between now and the end of this year. The banks says its partnership with MasterCard and Carlson Wagonlit Travel will enable the upgraded program. Comerica Corporate Card clients earn free tickets on any airlines with 20,000 miles of air travel, instead of the industry standard 25,000 to 40,000 miles. Under the program, blackout dates or similar restrictions, do not apply. The Comerica 'Corporate Card' suite includes a 'MasterCard Purchasing Card' and a 'MasterCard Fleet Card'. For more information www.comerica.com.