A category of stocks relating to the transportation of goods or customers. The transportation sector is made up of airlines, railroads and trucking companies. Taobiz explains Transportation Sector The performance of the transportation sector is sensitive to the price of oil. Because operations revolve around the use of vehicles, fuel prices represent a significant cost to transportation companies. As the price of oil rises, transportation companies will be expected to earn less. Inversely, these companies do well when the cost of fuel decreases.