The density of air _____ as an aircraft climbs and altitude ______.

The density of air _____ as an aircraft climbs and altitude ______.

• A. decreases, increases
• B. increases, decreases
• C. stays the same, increases
• D. decreases, stays the same

Answer: (A)

Air density decreases with altitude because the air becomes thinner as you go higher. As an aircraft climbs, there are fewer air molecules in a given volume, so density drops. The same holds as altitude increases—the higher you go, the more the air thins out. This is why the correct completion is that density decreases as the aircraft climbs and altitude increases. This change impacts performance, since less dense air provides less lift for the rotors and affects thrust and cooling. The other options imply density would rise or stay the same, which doesn’t align with how the atmosphere behaves.

Air density decreases with altitude because the air becomes thinner as you go higher. As an aircraft climbs, there are fewer air molecules in a given volume, so density drops. The same holds as altitude increases—the higher you go, the more the air thins out. This is why the correct completion is that density decreases as the aircraft climbs and altitude increases. This change impacts performance, since less dense air provides less lift for the rotors and affects thrust and cooling. The other options imply density would rise or stay the same, which doesn’t align with how the atmosphere behaves.