Rashtriya Lok Dal (RLD) chief Ajit Singh was today sworn in as a Union Cabinet minister. He is likely to get the Civil Aviation portfolio. This is the fourth time Mr Singh has been inducted into the Union Cabinet. The 72-year-old Jat leader from western Uttar Pradesh has become a part of the Manmohan Singh cabinet a week after his party formally joined the UPA, the first political outfit to do so since the alliance came to power for the second time in May 2009.