Quinjet

"We have soldiers willing to sacrifice, but they need weapons. The enemy has the advantage. We need one of our own." "You risked that for a quinjet?" "No. For what we can do with one."

- Phil Coulson and Alphonso Mackenzie

The Quinjet is a technologically advanced S.H.I.E.L.D. jet frequently used by the Avengers for transportation. Quinjets possess unique flight capablities thanks to their unique wings which contain ducted fans. While most early Quinjets were light on weapons, the former S.H.I.E.L.D. initiative: Project Insight introduced a series of Quinjets with a wider range of weapons.

Development
The Quinjet is an advanced aircraft used by S.H.I.E.L.D. and the Avengers for personal transport and aerial combat. There were several Quinjets active since the events leading up to Loki's invasion of Earth

War for Earth
Following Loki's arrival on earth and theft of the Tesseract, S.H.I.E.L.D. was put in a state of high alert, assembling various members of the Avengers and launching their Helicarrier, which carried a handful of Quinjet on board. A Quinjet was used as the transport that brought Steve Rogers and Phil Coulson aboard the Helicarrier.

In Stuttgart, Steve Rogers, Natasha Romanoff, and several S.H.I.E.L.D. agents arrived in a Quinjet to intercept a public attack by Loki. Romanoff attempted to take Loki out with the Quinjet's forward turret but couldn't make a clear shot. Tony Stark later hijacked the Quinjet's speaker system to play "Shoot to Thrill" as he made his entrance and swiftly took Loki out. However, as they were on their way back to the Helicarrier with their prisoner, the Quinjet was intercepted by Thor, who managed to force his way inside and make off with Loki.

A brainwashed Hawkeye and several mercenaries disguised as S.H.I.E.L.D. agents used a stolen Quinjet to attack the helicarrier and free Loki. During the attack, Hawkeye was captured, and several of the mercenaries were killed; however, Loki was able to escape using the stolen Quinjet.

Shortly after the attack on the Helicarrier, Captain America, Black Widow, and Hawkeye "hijacked" a Quinjet in order to get to New York City and head off Loki and the invading Chitauri; however, shortly after arriving, they are easily shot down by Loki and were forced to make an emergency landing.

Project Insight
During the S.H.I.E.L.D. initiative: Project Insight, an initiative created to monitor worldwide activity and provide a pre-emptive strike against global threats before they could escalate, a new series of Quinjets with heavier weapons capabilities were created to serve on the Project Insight Helicarriers. One such Quinjet was used against Captain America as he tried to escape from the Triskelion after being branded an enemy by Alexander Pierce.

Getting the Cloaking Technology
Phil Coulson sent Melinda May, Skye, and Antoine Triplett in to a Government Storage Warehouse that had multiple quinjets in order to steal one. He wanted it for the cloaking technology that quinjets have after he decided that using Leo Fitz to build cloaking technology for the Bus was inappropriate, given his condition.

The cloaking technology was reverse-engineered by Alphonso Mackenzie, with advice from Leo Fitz for the Bus. Afterwards, Coulson left a confrontation with Glenn Talbot in a cloaked Quinjet.

Undercover
After Jemma Simmons' cover in the HYDRA Laboratories was blown, Bobbi Morse had to drop her own cover, as the head of security, to help Simmons escape. After fighting off multiple HYDRA soldiers using her battle staves, Morse and Simmons fled to the roof, where according to Morse their escape route was located. They then jumped off the roof, landing on a cloaked Quinjet piloted by Antoine Triplett. They then flew back to the Playground.

May's New Plane
Melinda May piloted the Quinjet to Okinawa, Japan to follow a lead about Toshiro Mori. Afterwards, she flew the plane to Bruges, Belgium, but arrived too late to save Noelle Walters and her team from being massacred by Marcus Scarlotti and his mercenaries.

Coordinating her field agents between Philadelphia, Atlanta, and Boston, May piloted the Quinjet during S.H.I.E.L.D.'s hunt for Grant Ward after he escaped federal custody.

Surrounded
Dividing into two teams, Phil Coulson took Leo Fitz, Jemma Simmons, Alphonso Mackenzie, and Bobbi Morse with him to San Juan to search for the city that matched the City Blueprints in a quinjet, leaving Melinda May, Skye, Lance Hunter and Antoine Triplett on the Bus to help in the protection of Raina.

Aboard the plane, Mack talked to Morse about Hunter's knowledge of their mission and if he was replacing Isabelle Hartley on it; she told him that her ex-husband knew nothing about it and she did not want him involved.

In Puerto Rico, the silence between Fitz and Simmons grew too uncomfortable for Mack, so he chose to inspect the landing gear to give them privacy. Tearfully, Simmons attempted to explain why she left Fitz months ago to go undercover; he interrupted, explaining that he could not work with her. She asked if he was quitting S.H.I.E.L.D. He further explained that he wanted to work for her and made her leader of the science team. Four Quinjets owned by HYDRA surrounded the Bus when Grant Ward traced Raina's tracking device to find her for Daniel Whitehall. Ward promised that the HYDRA quinjets would not fire upon them if they relinquished Skye and Raina to him. Whitehall however told Agent 33 to order them to attack. Grant Ward took one of the four quinjets to San Juan to reunite Skye with her father. Meanwhile, the other three attacked the Bus. The HYDRA pilots believed that they had destroyed the plane when Antoine Triplett and Melinda May combined their piloting skills to fool them by cloaking after setting off an explosion.

Avengers Quinjet
The Avengers developed their own Quinjet for their unique situations.

Capabilities
The Quinjet is a unique, hybrid-wing aircraft with similar flight capabilities as modern VTOL aircraft and serves as a personnel transport and versatile attack vehicle. The Quinjet is able to reach high speeds through two powerful jet engines located at the rear of the ship. It possesses two large, angle-adjustable rotors, one housed in each wing, which grants the aircraft its vertical take off and landing capabilities. The Quinjet also has adjustable wing tips that can be angled down to intensify the lift of the wing rotors and modify the movement of the ship. This gives the Quinjet unprecedented maneuverability as it can make full stops mid-air, hover in place, and make incredibly tight turns compared to conventional aircraft.

The Quinjet also has a variety of weapons, the most prominent of which is a GAU-17/A Gatling gun mounted on the underside at the front of the jet. The Quinjets utilized on the Project Insight Helicarriers are more heavily armed than standard Quinjets, utilizing missiles mounted onto each wing as well as smaller missiles. However, they still utilize the same Gatling gun mounted on the forward underside of the jet.

Additionally, Quinjets have retro-reflective panel technology similar to the Helicarrier, which grants the Quinjets high level stealth capabilities and near invisibility from a far enough distance.

Trivia

 * The Quinjets used in Captain America: The Winter Soldier are slightly different from the ones used in The Avengers, as they are more heavily armed and lack the adjustable wingtips found on the older Quinjets, giving them a shorter wingspan. The new Quinjets also had linear aerospike engines across their tail, in addition to the usual turbojet engines. The aerospike engines were used for lower speed stealth flight, in combination with the turbofans in the wings.