What government agency aims to provide Americans and visitors with the safest air transportation system possible by regulating the construction and maintenance of most airports and maintaining oversight on airplane design and maintenance?

A. the Environment Protection Agency
B. the Federal Aviation Agency
C. the National Highway Traffic Safety Administration
D. the Food and Drug Administration

B. the Federal Aviation Agency

The correct answer is B. the Federal Aviation Administration (FAA). The FAA is a government agency that aims to provide Americans and visitors with the safest air transportation system possible. Here's how you can arrive at this answer:

1. To find the answer, consider the key elements of the question: ensuring safe air transportation, regulating airport construction and maintenance, and overseeing airplane design and maintenance.

2. Option A, the Environment Protection Agency (EPA), focuses primarily on environmental protection and regulation, not specifically on air transportation or airport and airplane safety.

3. Option C, the National Highway Traffic Safety Administration (NHTSA), is responsible for overseeing road safety and vehicle regulation, not air transportation.

4. Option D, the Food and Drug Administration (FDA), mainly deals with food, drug, and medical device safety and regulation. It is not directly related to air transportation.

5. Option B, the Federal Aviation Administration (FAA), is responsible for regulating and overseeing the safety of civil aviation within the United States. It is specifically tasked with regulating airport construction and maintenance, as well as airplane design and maintenance, making it the correct answer.

In conclusion, the correct government agency that aims to provide Americans and visitors with the safest air transportation system possible by regulating airport construction and maintenance, and overseeing airplane design and maintenance is the Federal Aviation Administration (FAA).

The correct answer is B. the Federal Aviation Agency.