When CLE was CO's third largest hub, it made marginal sense for CO (or perhaps even a SkyTeam partner airline) to offer (at least seasonal) service between CLE and ST hubs in Europe (e.g. Paris) or even non-ST-hub cities like London because its so popular. CO's CLE hub (especially at its height with nonstops all over the US) was a reasonable connection point outbound to or inbound from Europe, though CO never marketed it very well internationally. Now CLE is lucky to have a second tier carrier like IF or third tier like WW.