Final answer:
The fare code that can be used by senior citizens is called a senior citizen fare code, and the age requirement is usually around 60 years old.
Step-by-step explanation:
The fare code that can be used by senior citizens is usually referred to as a senior citizen fare code. This fare code offers special discounts or benefits for senior citizens when traveling. The age requirement to qualify for senior citizen fares may vary depending on the airline or transportation company, but it is typically around 60 years old. Therefore, the age requirement would be 60 years old and the fare code used is called as senior citizen fare code.