(Reuters) - Delta Air Lines CEO Ed Bastian said in a memo on Friday that he continues to expect that the company will achieve positive cash flow by the spring. In his new year note to employees, Bastian said that company will likely “experience two distinct phases during the next 12 months.” The first phase will be similar to 2020, he said. ADVERTISEMENT “The second phase will begin only when we reach a turning point with widely available vaccinations that spur a significant return to travel, particularly business travel.” Bastian had told investors in October that Delta plans to start paying down its debt in 2021 once it has positive cash flow. ADVERTISEMENT Revenues at Delta, which is blocking middle seats until March 30, fell 76% to $3.1 billion in the third quarter from a year earlier. “As difficult as 2020 was, in many ways I expect the next 12 months to be even more challenging,” he added. Reporting by Aishwarya Nair in Bengaluru; Editing by Lisa Shumaker