The Avengers team in Avengers: Endgame was able to travel through time within the Marvel Cinematic Universe with the help of powers of the Quantum Realm. The Avengers had to use specialized time-travelling suits. To prevent from being crushed by the forces of time, the costumes were required naturally. At one point the arc reactors are necessary for the outfit for the team to time travel. In addition to that, the arc reactors usage as recently evidenced by new concept art. From the past week, the grand revelation of the Quantum Realm concept art is available online.
Quantum Realm concept art
Aleksi Briclot recently shared the concept of the art online through an Instagram post. In the below-linked post, one can see the arc reactor-powered concept art suits resemble a popular kind T-shirt. The resemblance would have been a repelling article with the Disney brand. The t-shirt I am referring to can be seen in the gallery below. It seems the direction team tried and rejected the concept of art before they went with the Ant-Man style suits.
Russell Earl on the Suits
Earlier this year, Endgame visual effects supervisor Russell Earl revealed some facts in an interview. The suits in the movie were entirely computer-generated. Th whole team knows that the suits have to be built anyway. As a result, the CG helped to have a little bit more flexibility. This is due to the inclusion of nanotech growing out of the time watches. Through his interview, we knew more exciting insights into the movie-making. His interview confirms that the Ant-Man designed suits that are the makers built have been done in all CG. It also revealed that the characters at one point or the other are CG with the outfit.
Avengers: Endgame is now available on Disney+.