Chagrin:
Focus on the stall current which is the maximum current the motor will consume under its maximum load. That's 1A (or 1000mA). To drive two motors at full power for one hour you need 2Ah (2 amp-hours) or 2000mAh. An AA, rechargeable, NiMh battery just happens to be around 2000mAh.
Just to be clear, this is only under "ideal circumstances" - ie, not anything you would see in the real world.
If you look on the spec sheet a given battery, you will usually see a graph or equation for battery capacity "de-rating", generally due to heat (externally and internally generated), though other factors can come into play (heat is the main factor, though).
So - the best way to know is to find a given battery or cell of the capacity you think you'll need, look at the battery de-rating, and recalculate for the conditions you expect or think the battery will see (and adjust your sizing accordingly).