Air Canada’s Aeroplan, a Star Alliance member, is offering a bonus for transferring in points of up to 55,000 miles through April 18.
American Express Membership Rewards is excluded from this bonus. But Starwood points transfers (and most others) are eligible.
Aeroplan charges 55,000 points each way, 90,000 points roundtrip, per person for business class between the Continental US and nearer Europe.