Saudi Arabian Airlines has earmarked four subsidiaries for privatization during the course of this year. The move is meant to boost the airline's revenue stream.  The carrier has already privatized five other units including Catering, Saudia Cargo, Ground services and Saudia Aerospace Engineering Industries. In an interview with Arab News, Abdullah Al-Ajhar, the Saudi national carrier's vice president for public relations, said the units listed include the Prince Sultan Aviation Academy, Saudia Private Aviation , Medical Services, which include a 400-bed hospital, and Saudi Airlines Real Estate Development Company. “This year will witness the privatization of about 70 to 80 percent of our strategic units,” he said.Mr Al-Ajhar also noted that Saudia would acquire an additional 35 new aircraft to beef up services in the domestic sector. “We are still in the planning stage. We have yet to determine the model and size of the new aircraft,” he said.