(Reuters) - Delta Air Lines Inc on Wednesday lifted its 2019 revenue forecast after reporting better-than-expected quarterly profits, boosted by robust travel demand and a renewed agreement with credit-card issuer American Express Co. The No. 2 U.S. carrier said it is targeting full-year revenue growth of 5 to 7 percent, an increase from 4 to 6 percent previously, with the American Express deal expected to add about $500 million (382.47 million pounds) to 2019 revenue.Total operating revenues..