There is a supermarket in Brazil that is running a promotion that offers a discounted flight on Delta to Boston, NY, or Miami. It books into U class. I don´t have much experience with Delta and was wondering if someone can point me to a link with general U class restrictions. I´m also seeking information on others´experience as far as availablity of U class fares. I don´t want to waste my time if the availabilty is going to be so limited that it becomes too much of a hassle. Thanks.