http://www.aircanada.com/en/news/110502.html?src=hp_wn

Effective for travel as of August 1, 2011, the minimum number of Aeroplan Miles accumulated based on distance flown on Air Canada and Star Alliance member airline flights is changing from 500 to 250 miles:

For distance flown up to 249 miles, Aeroplan members will earn 250 Aeroplan Miles.

For distance flown of 250 miles and more, Aeroplan members will earn miles according to the actual miles flown


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However in a nod to potential outrage:

"This new policy will not impact Air Canada Super Elite, Elite and Prestige members, nor customers travelling on Rapidair flights between Toronto Pearson International Airport and Montreal or Ottawa, or between Toronto City Airport and Montreal as they’ll continue to earn a minimum number of 500 Aeroplan Miles."