Utilize the input text as a context reference, choose the right relationship between FedEx and FedEx Ground from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

All totaled, our first quarter adjusted operating income increased 56% year-over-year primarily due to international priority volume growth of 31%, a surge in demand for U.S. residential delivery, yield improvement at FedEx Ground and FedEx Freight, a $130 million benefit from an additional operating day, a $65 million benefit from a reduction in aviation excise taxes provided by the Cares Act and a better alignment of our expenses, especially at FedEx Freight.
subsidiary