When the first Star Wars spin-off film was revealed to be called Rogue One: A Star Wars Story, fans reacted with excitement. Director, Gareth Edwards, said it would be a war film with a crew who had worked on films like Saving Private Ryan and Zero Dark Thirty. The original Star Wars films also took a lot of inspiration from real wars. The most common influences on George Lucas for many of the battle sequences derived from World War II and Vietnam.
World War II and Star Wars
World War II was a direct influence on the look of the Empire. Similar to Nazi Germany, the Galactic Empire is militaristic and devoted to a single ruler. In The Force Awakens, Nazi rallies, including the mass salute at the end, inspired the First Order rally. Also, Imperial Stormtroopers are named after German Stormtroopers which served as elite shock units in both World War I and II. Stormtroopers were often used to strike fear in opposing armies much the same way the first Star Wars film portrays them as fearsome soldiers.
By contrast, the Rebel Alliance was based on resistance movements to the Nazi regime. Unlike the Empire, the Rebellion has scrapped together technology and the Empire regarded them as little more than a nuisance. Many Resistance groups were treated the same way by Germans until bolder strikes caused them to take the threat seriously. This is similar to the way the Empire dismisses the Rebel Alliance until they destroy the first Death Star. After that event, the Empire begins to hunt down the Rebellion which leads to the Battle of Hoth.
Lucasfilm would go back to the well in later projects. For the animated film, The Clone Wars, a voice-over narration substituted the opening crawl. This was influenced by old World War II radio broadcasts. The broadcast style would continue into the animated show of the same name.
Inspired by WWII Fighter Planes
In the original Star Wars, when George Lucas designed the dogfight between the Millennium Falcon and Imperial Tie Fighters, he looked at real World War II dogfight footage and edited them into the sequence. Aerial dogfighting inspired the final attack on the Death Star. It took the common concept of bomber planes attacking a target and fighter planes defending their attack. We see this in the film with Y-wing bombers running the trench protected by X-wing fighter group Red Squadron.
Vietnam and Star Wars
For the third Star Wars film, Return of the Jedi, Lucas wanted the final battle to symbolize the Vietnam War. He wanted to show an outnumbered group of rebels defeat an army with superior technology. This led to the creation of a primitive race called Ewoks who would use guerrilla tactics to defeat Imperial Stormtroopers and AT-ST walkers. Wookiees were supposed to be used, but they were already established as technologically proficient.
The aftermath of the Vietnam War is considered a part of the success of Star Wars. After the U.S. defeat, there were many people who sought escapism and adventure in a good war film that had clear heroes and villains. Star Wars fit that bill for many, making it a huge blockbuster.