There's no potty onboard. Flights may be planned around maximum passenger endurance (typically 3 hours or less). Restrooms are immediately available at most destinations.
Maximum passenger weight is 250 lb. Larger passengers may not fit the emergency exit.
Hazardous materials: Carry-on and baggage rules are the same as for any airline flight. More detail at "Hazardous Materials".
Devices: Laptops and smaller are okay but may not transmit during flight (i.e., use "airplane mode").