Final answer:
The provided context does not pertain to Bill Gates but rather describes a character named Ahaya taking measures to prevent deep vein thrombosis by pacing up and down the aisle during a flight.
Step-by-step explanation:
The question seems to be based on a misunderstanding or fictional narrative, as there is no historical record or public information to suggest that Bill Gates had an incident involving an airline returning to the gate on his account. However, the context provided in Figure 17.1.1 does not discuss Bill Gates but a character named Ahaya, who is pacing in the airplane aisle for health reasons. Ahaya is doing this to prevent the formation of a blood clot in his legs, a condition known as deep vein thrombosis (DVT). DVT is a serious health concern during long flights as sitting for extended periods can increase the risk of blood clots. To mitigate this risk, it's recommended to walk around, stretch, and perform foot and leg exercises, as Ahaya was doing.