The aircraft (10) comprises a fuselage (11) and a rhombohedral wing structure (12) comprising front wings (13, 14) mounted on a front wing-root support (17) and rear wings (15, 16) mounted on a rear wing-root support (18). One end of each front wing is articulated to one end of a rear wing and at least one of the wing-root supports is able to move along the fuselage. The wing-root supports (17, 18) are positioned respectively underneath and on top of the fuselage (11).