Airline stocks including American Airlines Group Inc (NASDAQ:AAL) and United Airlines Holdings Inc (NASDAQ:UAL) are losing altitude Thursday in sympathy with Delta Air Lines Inc (NYSE:DAL), which fell on second-quarter earnings results. What Happened With DAL: Delta reported second-quarter revenue of $16.658 billion, beating the consensus estimate of $15.452 billion. The company reported second-quarter adjusted earnings of $2.36 per share, missing estimates of $2.37 per share, according to estimates from Benzinga Pro. Delta also guided for third-quarter revenue growth of 2% to 4% and adjusted earnings of $1.70 to $2 per ...