Botswana, a state-owned airline that is being sold to private investors, the Public Enterprises Evaluation and Privatization Agency said. The short-listed companies include Comair Ltd., a South African carrier, Ethiopian Airlines and Lobtrans Ltd., a Botswana fuel transporter, Joshua Galeforolwe, chief executive of the Gaborone-based agency, said in a telephone interview today. Bidders must ``meet the government's strategic objective of having a robust, reliable and safe air transport service to meet the growing demand by the tourism sector, the business community and the public in general,'' he said. Botswana is selling state-owned assets to improve their efficiency. Air Botswana operates four southern African and three domestic routes, carrying 150 000 passengers a year, 38% of total air travelers in Botswana, according to its Web site. The airline generates annual revenue of $20-million. Other short-listed bidders include Tourism Empowerment Group Ltd., a South African tourism company, ExecuJet Aviation Group, a Zurich-based air charter company, and South African Air Link, a closely held Johannesburg-based airline. Botswana plans to sell the airline before the end of the year. It hasn't disclosed the size of the stake it intends to sell. The southern African country is the world's largest diamond producer and the nation with the highest credit rating in Africa, rated A2, the sixth-best investment grade, by Moody's Investors Service. Shares in Comair were unchanged at R1,