Originally Posted by
xliioper
No. What you are describing is likely due to the fact that US/Canada fares are generally priced at the same dollar amount in both directions. When you book a roundtrip ex-US, both outbound and return fares will be priced in US dollars. When you book as separate one-way's, the flight ex-US will be in US dollars, but the return will be priced in Canadian dollars and is cheaper due to the exchange rate. This assumes that there aren't cheaper roundtrip fares available which can defeat the advantage of purchasing as two one-way's. This has nothing to do with what OP is doing which is a simple one-way. These are both CUR-DCA fares being quoted, it's just Google is quoting a cheaper CUR-DCA I fare, while aa.com is quoting a more expensive CUR-DCA R fare due to the lack of married segment availability which Google Flights seems to be ignoring.
No. In the scenario I described, the price difference was significantly more than anything that could be blamed on the exchange rate. The agent specifically commented about the fare being based on the country of origin (but it was nothing to do with currency conversion). I'm not suggesting you're incorrect about the OP's situation, however.