Hong Kong, April 14 -- Australia's domestic passengers flying in business class or purchasing restricted economy tickets enjoyed air fare relief this month compared with a year ago, local data reveals. Read More Figures published by Australia's Bureau of Infrastructure and Transport Research Economics (BITRE) show the measure of restricted economy fares has fallen 22.2%, or 18.2 index points, to 64 points. The business class measure was 8.4% lower at 53.1 points. However, potential travellers searching for the cheapest air tickets were likely left disappointed with the BITRE best discount measure rising 12.5 index points (20.8%), to 60 points. "The series is a price index of the lowest available fare in each fare class weighted over selecte...