A bit like British Midland the Northwest name had historical regional connotations whereas Delta is a “global” name that an airline anywhere could theoretically use added to which,prior to the last 10-15 years,Delta would have been seen as the best US airline by far even if Pan Am and TWA were better known.Indeed,I’ve never understood how they’ve fallen so far financially except,perhaps,they’ve not had the International OR domestic route structure that those in “alliances” have built up.

B