The creation of the airline alliances has allowed airlines to serve a wider range of routes than they could sustain themselves.  Part of their obligation as a member of the alliance is to have some of their aircraft painted in alliance colors.  Sadly, these liveries are not that exciting but I suppose it is some variety.  I was quite surprised to get an Air France 777-300ER in SkyTeam colors vacating the runway at the same time a United 777-200ER in Star Alliance colors was taxiing the opposite direction.  I felt like the scene for a stand off but no such thing occurred.