ToplineShares of Delta tumbled 7% on Thursday, pacing the company’s worst loss so far this year, after the airline reported a decline in earnings and forecast lower profits for the upcoming quarter that fell short of analyst expectations.The airline said it remained optimistic for increased summer travel in the upcoming months. Getty Images Key FactsDelta’s shares dropped to about $43.50 as of around 10:15 a.m., following an earlier plunge in premarket trading as low as 10%. The stock’s furthest fall befor ...