If you mean international = over water (not Canada, Caribbean, etc), then that would be the A350, A330, and 767-400 that almost exclusively fly international. Those fleets will all have some domestic mixed in from time to time, but generally that will be a very small percentage of the flying. The other fleet that does international is what we call the 7ER category, currently in SEA (but closing soon), ATL, LAX, and NYC. This category includes the 757-200, 757-300, and the 767-300. Every base is going to have a different mix, but the 757's are almost exclusively domestic except maybe for a few routes, while the 767's do both. The percentage of domestic vs international is going to vary by base and by month. Generally if you're junior it's harder, but not impossible, to get international flying as a line holder. While you may not get anything on your initial award you could probably snag stuff as people drop trips into open time or via the swap board.