Answer: Air travel is a normal good and vacation travel by car is an inferior good
Explanation: What is a normal good and what is an inferior good.
Normal goods are those goods for which the demand rises as consumer income rises. While inferior goods are goods whose demand increases when consumer income decreases.
This therefore means that the demand of inferior goods is inversely related to the income of the consumer.
From the question above, we can say that car trips are inferior goods while the air travel are normal goods.