World War Air, Land and Sea
Basic risk with some twists
Normal 6vs6 attack dice except for planes and ships.
Attack to a ship is 6vs6.
Attack from ship to land is 5vs6. You can fortify to any boardering territory.
Attack from plane to land is 5vs6. You can fortify to any boardering territory.
Planes and ships attack each other with 6vs6.
Ships are the only way to gain access to the planes from land.