Direct costs. include, but are not limited to, salaries, travel, equipment, and supplies directly benefiting the grant-supported project or activity. If directly related to a specific award, certain costs that otherwise would be treated as indirect costs.
Airlines are in business to make money and even though they may be on the receiving end of government bailouts from time to time, the bulk of their revenue comes from travelers. Aside from the cost of tickets themselves, airlines can also collect fees from passengers that help to add to their profit margins.