Originally Posted by Brendan

Alexxgr, yes, do phone Aeroplan. Their Website is mediocre at showing availability. Any *A flight available on UA miles should be available on AC miles. Be sure to ask about the direct flight ATL--FRA, probably on LH! Only bad thing about using AC miles vs. UA is that AC charges ~$300 in Fuel Surcharges ("YQ") on its own flights & certain partners.
Also, try to talk them out of the Phone Booking Fee by pointing out that U tried to book the direct flight online, but it did not display!
Remember that you're allowed 1 (or is it 2) "stopover(s)" (spending days in a city on the way to your main destination OR 1 stopover + 1 "open-jaw" (mixing of cities.) Do you really want to go ONLY to Frankfurt, or also somewhere else?