Who determines the members of the presidential aircraft and entourage?

The correct answer is that the White House determines the members of the presidential aircraft and entourage. This process involves coordination among various staff within the White House, including the President's own administration and security personnel. The White House staff plays a crucial role in managing logistics for presidential travel, which encompasses selecting appropriate personnel to accompany the President based on the nature of the trip and the President's responsibilities.

The other options represent roles that may be involved in presidential travel in different capacities but do not have the primary responsibility for determining the members of the entourage. For instance, while the President ultimately makes key decisions regarding who travels with them, the operational details—including who specifically is included—are generally handled by White House staff. The Secretary of State and the Department of Defense may influence decisions regarding travel concerning foreign policy and security, but the final determination rests with the White House operations team.