As the Belgian pilot said, A300's are much more popular in Europe, so chances are much bigger the 767 will be operated in the US.
Very few carriers in Europe use B767 cargo, meanwhile here in South America the 767 is very common but hardly A300's in use.
Distances are shorter in Europe and payload of the 767 is higher and more common to cross the Atlantic ocean.
But slowly also in Brasil the interest of the A300 is starting ( B4) for inland transport to replace the B707 and DC 8's, as also our Civil Aviation is getting stricter every year. The 300-600 is too expensive for inland use and payload to low to cross the Atlantic.