Stacking with friendly units: You only have three friendly units in a single hex, and only one of them can be a vehicle.
The stacking limit only applies at the end each phase. Units can temporarily exceed the stacking limit during the movement or assault phase. Units that exceed the stacking limit are moved back to the previous occupied hex if possible until the overstack is corrected.
Aircraft: Instead of each player placing all of their aircraft during their own flight phase, players alternate placing aircraft with the first player placing the one aircraft, the second player placing the one aircraft. Continue alternating placement until both players have placed all of their aircraft.
Artillery units without the Antiair ability cannot attack aircraft. The ability Crack Shot doesn’t give +1 to attack rolls against aircraft.
Building an Army: There is no limit on the number of units that an army can contain.
A max of 10% of the army can be spent on Obstacles.
Armies can be of 100, 200, or 400 point value. An army of 200 points (or less) is the suggested standard army.
A player’s army has be constructed within the following historical limitations:
German, Hungarian, Rumanian, Slovakian, and Italian units can go in the same army.
Soviet units can’t be in army with any other nationality.
Japanese units can’t be in an army with any other nationality.
Units from the United States, the United Kingdom, Australia, South Africa, and Canada can be in the same army.
Units from France, Belgium, and the United Kingdom can go in the same army.
Nationalist Chinese can be in the same army as United States and United Kingdom units.
Polish units can’t be in an army with any other nationality.
Free Polish units (Polish units deployed after 1939) and Free French (French units deployed after 1940) can be in the same army as United States, Canadian, Australian, South African and United Kingdom units.
Units from Greece and the United Kingdom can be in the same army.