An aircraft capable of hovering, in particular a helicopter or a convertiplane, comprising: - a fuselage; - a main transmission group; and - a main rotor (3, 3', 3", 3'"), which is connected to said main transmission group and is adapted to provide said aircraft with the lift to raise it; said main rotor (3, 3', 3", 3"') comprising, in turn,: - a stationary support structure fixed to said fuselage; - a rotative element, which is rotatable about a first axis with respect to said stationary support structure; - at least one blade which is operatively connected with said rotative element; - a source of a magnetic field, which is either stationary or driven, in use, in rotation at a first rotational speed (ω1); and - an electric conductive element, which is operatively connected to said rotative element and can be driven, in use, in rotation at a second rotational speed (ω2) different from said first rotational speed (ω1); said electric conductive element being electromagnetically coupled with said source, so that an electromotive force is magnetically induced, in use, in said electric conductive element itself; said rotor (3, 3', 3", 3"') further comprising: - a hub (12, 12') operatively connected to said rotative element, rotatable with said second rotational speed (ω2) about said first axis and onto which said blade is articulated; and - a support element (36, 36', 36") to which said source is fixed, and which is either stationary or rotatable with said first rotational speed (ω1) about said first axis; said electric conductive element being fixed to said hub (12, 12'); said rotor (3, 3', 3", 3"') comprising a flow deflector made in metal, which is arranged at an axial end of said rotor (3, 3', 3", 3"'), is rotatable about said first axis integrally with said hub (12, 12'); characterized in that said flow deflector comprises a plurality of thermally conductive rings and defines a compartment housing at least in part said support element (36, 36'); said hub comprising: - a tubular body and a first and a second ring (52, 53) which extend from said body towards said first axis and orthogonally to said first axis; said electric conductive element being fitted to said second ring; said plurality of thermally conductive rings being connected to said first ring; or said hub comprising, as an alternative to said first and second ring (52, 53),: - an annular disk protruding from an axial end of a body arranged on the side of said flow deflector towards said first axis and lying on a plane orthogonal to said first axis, and to which said plurality of thermally conductive rings are connected; - a cylindrical wall protruding from a radial inner end of said disk towards said support structure, coaxial to said first axis and having an axial length smaller than said body; and - a ring protruding from an axial end of said cylindrical wall opposite to said disk, lying on a plane orthogonal to said first axis, and to which said electric conductive element is fitted. - a fuselage; - a main transmission group; and - a main rotor (3, 3', 3", 3'"), which is connected to said main transmission group and is adapted to provide said aircraft with the lift to raise it; - a stationary support structure fixed to said fuselage; - a rotative element, which is rotatable about a first axis with respect to said stationary support structure; - at least one blade which is operatively connected with said rotative element; - a source of a magnetic field, which is either stationary or driven, in use, in rotation at a first rotational speed (ω1); and - an electric conductive element, which is operatively connected to said rotative element and can be driven, in use, in rotation at a second rotational speed (ω2) different from said first rotational speed (ω1); - a hub (12, 12') operatively connected to said rotative element, rotatable with said second rotational speed (ω2) about said first axis and onto which said blade is articulated; and - a support element (36, 36', 36") to which said source is fixed, and which is either stationary or rotatable with said first rotational speed (ω1) about said first axis; - a tubular body and a first and a second ring (52, 53) which extend from said body towards said first axis and orthogonally to said first axis; - an annular disk protruding from an axial end of a body arranged on the side of said flow deflector towards said first axis and lying on a plane orthogonal to said first axis, and to which said plurality of thermally conductive rings are connected; - a cylindrical wall protruding from a radial inner end of said disk towards said support structure, coaxial to said first axis and having an axial length smaller than said body; and - a ring protruding from an axial end of said cylindrical wall opposite to said disk, lying on a plane orthogonal to said first axis, and to which said electric conductive element is fitted.