What is the main difference between aerobic respiration and anaerobic respiration?

The main difference between aerobic respiration and anaerobic respiration is that aerobic using oxygen in the reaction, while anaerobic does not.

Even though both aerobic and anaerobic respiration releases energy, but their reactants and other products are completely different.
For example in human, in aerobic respiration, oxygen and glucose reacts to give out carbon dioxide and water; while in anaerobic respiration, which usually happens during exercise when oxygen is not enough, the muscle cells uses only glucose to produce energy and lactic acid.

Therefore, the main difference is where aerobic uses oxygen, and anaerobic don’t.