it space is airless why do film makers insist on showing fire in space?

As others have pointed out, explosives include their own oxidants that could allow for the presence of brief - but not sustained - flames in space.

But the larger issue is that filmmakers take broad dramatic license when depicting action in space. It's the same reason that space scenes usually have sound.

Well for one thing many of the fires in the movies are when a spacecraft is hit with some weapon. Spacecraft would be full of air, which contains oxygen. This oxygen venting could result in a fire in space..... Granted it wouldn't last long, nor likely be as spectacular as those in the movies. But regardless, a movie that obeyed every single law of physics probably wouldn't win any awards for visual effects.

Shouldn't a better question be if space is airless why do we keep hearing explosions?

as space is a vaccum there is no air so there cannot be fire but films are just trying to sell it everything dose not have to be based on the truth.

You could have a fiery explosion in space provided that the thing exploding had oxygen in it (which it probably would if it were a spaceship.) But the explosion would be silent.

and explosion is different than flames. An explosion comes from a source where there is chemical energy, ie inside a spaceship (which has an oxygenated atmosphere presumably)

A flame is a plasma, which is a super heated gas. So you can get flame in space only it'll behave very differently as it'll expand so quickly.

All "explosives" carry their own oxidants and don't require air.

BECAUSE FILMAKERS ARE NOT SCIENTISTS. What the hell do they care if the science is off?