In cinema, there are multiple misconceptions about time travel, one of which involves traveling back in time. First of all, it is true that we can travel to the future. When a rocket moves at a high speed, the rocket's time feels slower than that outside of the rocket. However, it is impossible to travel into the past due to multiple paradoxes and the difficulty of implementing equations in Einstein's theory of relativity. One such paradox is the Grandfather Paradox, which is one of the reasons scientists believe that traveling to the past is impossible. The paradox states that if one were to go back in time and kill their grandfather, their grandfather would not have a son. As a result, the time traveler's father (or dad) would not be born, and therefore, the time traveler himself would not exist. Consequently, the time traveler would not be able to go back in time to kill his grandfather. This is one of the many reasons why traveling to the past is close to impossible, unlike how it is often easily depicted in cinema.

Another main misconception from movies about time travel is the movement of light. Star Wars, for example, have a false visualization of traveling at the speed of light, or as the series likes to call it; hyperspace. In the show, it is shown that when traveling at the speed of light, stars appear to be longer, as if it is sliding. However, in Einstein's theory of relativity, it is shown that as objects move at a high speed, light tends to appear shorter. Therefore, in reality, hyperspace would closer look like a flashlight shining at the spaceship. Furthermore, even though characters are moving at such high speeds during hyperspace, there seems no time dilation. If it were to be more realistic, characters will age quicker while waiting for characters to travel between planets. 

In the movie "Endgame," Tony Stark is shown building a time machine through the quantum realm. However, there are multiple unrealistic aspects of time travel portrayed in the movie. First of all, it is unrealistic how Tony Stark was able to create a time travel machine in a single evening. Although Tony is considered a genius, it is hard to believe that he could devise such a complex machine just based on the knowledge that Antman had a time dilation experience in the quantum realm. Developing this technology in a matter of hours seems highly implausible. 

Furthermore, we must also consider the level of sophistication of the time travel machine. While it has been theorized that time travel in the quantum realm could be possible in the real world, Tony's ability to plan and construct a quantum realm time machine in a day, and make it work flawlessly on the first try, is extremely unrealistic. Building such a device would likely require extensive research, testing, and iterations before achieving a functional time travel mechanism.