UPDATE 1-Delta pilots oppose big regional jets, could be issue for Embraer, Mitsubishi

MONTREAL, Nov 25 (Reuters) - Delta Air Lines Inc pilots are expected to keep existing rules in their new labor contract that prevent the U.S. No. 2 carrier from flying aircraft above a certain weight on regional routes, in a blow to Embraer SA and Mitsubishi Heavy Industries Ltd , whose latest models exceed that limit.