Delta shares fell more than 5% Thursday after the airline forecast lower-than-expected quarterly profit — despite a surge in travel this summer.The Atlanta-based carrier Delta blamed discounting pressure in the low end of the market for dampening its pricing power as it predicted an adjusted profit between $1.70 and $2.00 per share in the third quarter through September, compared with analysts’ expectations of $2.05, according to LSEG data.The lowered profit expectations come as airlines are enjoying a summ ...