1 Wall Street Analyst Thinks This High Flying Stock Has 57% Upside. Is it a Buy?

Delta Air Lines' (DAL 0.31%) recent investor day presentation prompted a slew of upgrades from heavyweight financial companies, including Deutsche Bank, UBS, Citi, and most notably, Morgan Stanley, whose analyst maintained an overweight rating and slapped a $100 price target on the stock -- a figure implying 57% upside at the time of writing. Is Wall Street irrationally exuberant, or are the price target hikes justified?The numbers make Delta Air Lines stock a buyStarting with the three- to five-year target ...