WASHINGTON—Delta Air Lines will raise pay by 4 percent for nearly all its employees globally effective May 1, according to a company memo seen by Reuters. A company spokeswoman, who confirmed the increase, said it would be received by about 75,000 employees, but that it would not apply to pilots, who are covered under a union contract, and some others including senior-level executives. Delta Chief Executive Ed Bastian said in the memo to employees that the Atlanta-based airline is “seeing healthy demand for spring and summer travel as customers continue to return to Delta, with corporate offices re-opening, business travelers rebuilding face-to-face relationships, and international restrictions lifting.” The “base pay increase, for eligible scale and merit employees globally,” Bastian wrote, “is the direct result of the dedication, hard work, and excellence that you demonstrate every day.” He added that Delta continues to be “optimistic in our ability to generate a …