The Airjet Carrier is an ultimate introduced in the 13.0.0 update.
It appears to be an aircraft carrier with two planes in which one is flying and the other is still parked. The carrier has a gray paint job and an asphalt deck. There is a white control tower on the deck.
It serves as a base for fighters that attack enemies on the battlefield.
At this moment, ultimates like this are not in the game. It is expected that ultimates will be added to the game at some point due to the fact that the player is able to browse them in the clan fort section, and also in the clan storage, which is quite misleading. At the moment, it is unsure if an ultimate will be an ability used once per game, or if it will be constant.