Step-by-Step Solution:

1. Analyze the reaction conditions: The question asks for the products formed when sodium metal (Na) undergoes combustion in excess air. Air is primarily composed of oxygen (~21%) and nitrogen (~78%), along with other gases like water vapor. Combustion refers to a high-temperature exothermic redox reaction between a fuel (sodium) and an oxidant (oxygen from the air).

2. Recall the reactivity of alkali metals with oxygen: The nature of the oxide formed by an alkali metal upon reaction with oxygen depends on the specific metal. The stability of peroxide and superoxide ions increases down the group.

   • Lithium (Li) forms the simple oxide, $Li_2O$.
   • Sodium (Na) primarily forms the peroxide, $Na_2O_2$.
   • Potassium (K), Rubidium (Rb), and Cesium (Cs) form superoxides, $MO_2$.

3. Identify the major product for sodium: When sodium is burned in an excess supply of air or oxygen, the principal product is sodium peroxide ($Na_2O_2$). The balanced chemical equation for this reaction is: $2Na(s) + O_2(g) \xrightarrow{\Delta} Na_2O_2(s)$

4. Identify the minor product for sodium: While sodium peroxide is the major product in excess oxygen, some amount of the simple sodium oxide ($Na_2O$) is also invariably formed as a minor product. This happens because the reaction might proceed in steps, or there might be localized regions with a limited supply of oxygen. The formation of sodium oxide occurs when the oxygen supply is limited: $4Na(s) + O_2(g) \xrightarrow{\Delta} 2Na_2O(s)$ Since the question asks for the "compound(s)" formed, we must include both the major and minor products of the reaction with oxygen.

5. Evaluate the given options:

   • A: $Na_2O_2$ (Sodium peroxide): This is the major product of the combustion of sodium in excess air. Therefore, option A is correct.
   • B: $Na_2O$ (Sodium oxide): This is a minor product formed during the combustion of sodium in excess air. Therefore, option B is also correct.
   • C: $NaO_2$ (Sodium superoxide): Sodium superoxide is not typically formed under these conditions. Its formation requires high pressure and temperature. Therefore, option C is incorrect.
   • D: NaOH (Sodium hydroxide): Sodium hydroxide can be formed if the primary products ($Na_2O_2$ and $Na_2O$) react with moisture (water vapor) present in the air. $Na_2O + H_2O \rightarrow 2NaOH$ $Na_2O_2 + 2H_2O \rightarrow 2NaOH + H_2O_2$ However, NaOH is a secondary product of reaction with atmospheric moisture, not a direct product of combustion with oxygen. The question asks for the compounds formed upon combustion, which primarily refers to the reaction with oxygen. Therefore, option D is generally not considered a direct product of combustion.

6. Conclusion: Based on the analysis, the compounds formed upon the combustion of sodium in excess air are sodium peroxide ($Na_2O_2$) as the major product and sodium oxide ($Na_2O$) as a minor product. Thus, both options A and B are correct.