The military jet in GTA V that can hover is the Hydra. It uses vertical takeoff and landing, or VTOL, technology, allowing its engine thrust to point downward for hovering and upward or backward for conventional jet flight.
That design makes the Hydra unusually versatile. It can lift off without a long runway, remain nearly stationary in the air, rise vertically, and then switch into fast horizontal flight. In gameplay, this lets pilots land in tight spaces and attack targets from angles that ordinary fighter jets cannot easily manage.
The Hydra is thematically modeled on real VTOL military aircraft, especially the Harrier family of jump jets. It is armed with machine guns and missiles, making it useful in both air combat and ground attacks. Its hover mode is powerful but requires careful control because the aircraft becomes slower and less stable than it is in forward flight.
The P-996 Lazer is another military jet in GTA V, but it does not have the Hydra’s dedicated VTOL hover capability. The Seabreeze is a smaller amphibious aircraft, and the B-11 Strikeforce is a heavily armed attack aircraft. Those distinctions make Hydra the single canonical answer.