For Ethan Hawke, an actor who has become so many different characters in his career, playing the drone pilot Tom Egan in “Good Kill” (now showing at the Gene Siskel Film Center) presented some challenges he hasn’t faced before.

In the film, his character is technically skilled at piloting unmanned drone aircraft over Middle Eastern targets in the war on ISIS. However, the professional soldier feels disconnected from his original flight training as he sits in a trailer in the Nevada desert killing terrorists half a world away.

Hawke said that if “this film had been made back in 2005, people would have thought this was the most dystopian, f’d up film that wouldn’t have seemed as real as it does today.

“That’s because we know so much about contemporary warfare, the Middle East conflicts and the battle against the threat of terrorism,” said the actor, calling from his home in New York.

Egan represented a contrast from Hawke’s own personality. “As you know, I’m a person who talks all the time. So it was wonderful to have the challenge of playing someone who can’t speak, who is so withdrawn and silent. He hates what he’s thinking. Anything that comes out of his mouth he doesn’t like, because he often says the wrong thing. So he doesn’t talk.”

To get himself in the right taciturn mindset, Hawke said he “thought a lot about Robert Redford in ‘Jeremiah Johnson’ when I was preparing for this — and even while we were shooting. That’s a great silent performance. He [Redford] is good at that. I gave myself that kind of challenge because it was difficult.

“But the downside is you can’t help your scene partners out — the other actors. It made it extra hard for people like January [Jones, who plays his wife]. I was no help. I couldn’t help the pacing. I couldn’t make it funny or whatever.”

But that was important to Hawke because he looked at Egan as a guy who has, in a sense, been plunged into deep depression — a mourning for his earlier life.

“I kind of looked at him as a person who is grieving,” said Hawke. “He was grieving for the loss of aviation, and the loss of his identity.”

The drone pilots of “Good Kill” and their families live outside of Las Vegas — something that is true in the real military.

“They based those people there because the terrain is so similar to Afghanistan,” Hawke said. “The landscape is pretty much the same. The sun sets on Vegas when it rises in Afghanistan. It’s kind of fascinating, when you think of it.”

This is Hawke’s third film with director and writer Andrew Niccol, and the actor thinks “Good Kill” would make “a good double-feature” with “Gattaca,” the first movie the two made together.

“Here’s my reasoning,” said Hawke. “Andrew is such an amazing writer and has a great gift for telling a story — especially when it involves the intersection of technology and humanity. … In ‘Gattaca’ he was talking about genetic engineering, something that has good aspects to it, as it could help in eradicating bad things from life, like diseases.

“But it raises huge ethical questions about designing human beings.

“The same thing is true in ‘Good Kill’ and the subject of predator drones. Here is something that is completely changing the landscape of the battlefield and the way wars are being conducted now, and obviously going into the future.

“Those drones are a huge resource, because they do take a lot of the danger out of it for pilots engaged in combat. But it also is another total opportunity for us to lose our humanity.

“There is a long history of war and cinema,” added Hawke. “It’s a legacy that has been captured in many, many movies. What’s nice here in ‘Good Kill’ is that I believe we’ve added something new to that legacy that has not really been seen before. I think it provides a unique angle on the whole issue of warfare for my generation.”