Children play on a destroyed fighter plane in Juba. Fragile hopes for an end to South Sudanu2019s civil war are being tested by the rebel leaderu2019s failure to return to the capital to form a unity government. International pressure is growing after Riek Machar, a former rebel leader turned deputy president who was fired, became a rebel leader again and has now fought his way back to the vice presidency, failed to appear in Juba as expected earlier this week.