The YF-19 is an experimental variable fighter featured in the Macross Plus OVA and its theatrical adaptation, Macross Plus Movie Edition. It was part of U.N. Spacy's Advanced Variable Fighter initiative under Project Super Nova. The prototype was piloted by Isamu Alva Dyson.
The design was ultimately chosen over the YF-21, with its final iteration being the VF-19 Excalibur which was featured in Macross 7 and subsequent spinoffs.

The YF-19 was designed with several technologies that would become the standard for those next generation variable fighters built to fulfill the operational demands of the UNAF/UNS. These technologies included an active stealth system, an anti-projectile shield, an optional fold booster for interstellar travel and a fighter-scale pin-point barrier system which sheathed portions of the variable fighter in an energy barrier that could move across the hull to intercept and defeat incoming fire. Installed Shinnakasu thermonuclear engines provided the YF-19 with unparalleled thrust, also allowing the variable fighter to attain orbital velocity over an Earth-class planet unassisted.

The VF-11 achieved much for Shinsei Industries with a stripped-down, basic design but the YF-19 benefited from advances such that Shinsei built the craft with much greater standard ordnance. Superior miniaturization and the larger airframe of the YF-19 created space for internal missiles mounted in the engine/leg units that maintained the variable fighter stealth capabilities. With up to four internal missile palettes, the YF-19 additionally utilized a fixed rearward anti-aircraft laser gun turret, two semi-fixed converging energy cannons in each wing (optionally laser cannons) and a new Howard GU-15 standard external Gatling gun pod (with field-replaceable magazines).

The YF-19 transformation time is 20% less than the VF-11 Thunderbolt and pilot survivability in Battroid is improved over traditional VFs due to the cockpit being stored inside the body rather than at the front of the body. The YF-19 was initially a difficult craft to operate in the testing phase and was flown by seven different test pilots during various trials. Shinsei was nonetheless determined to move forward and the YF-19 achieved incredible success in the Super Nova AVF, proving that Shinsei could rely upon practical proven methods for a superior next generation variable fighter.