A braking force generation device is configured to have: a first mode in which a deflector and a blocker door are retracted with respect to a wing; a second mode in which, in a state where: (i) a leading edge of the deflector is separated from the wing; (ii) a trailing edge of the deflector is at or adjacent to the wing; and (iii) the blocker door is deployed: a first flow path is formed on a lower surface side of the deflector for fluid to flow from a rear of the wing to a front of the wing via a cross flow fan from an opening on a blocker door side to a leading edge opening on a leading edge side of the deflector in the first flow path; and a third mode in which a second flow path is formed on the lower surface side of the deflector.