Steven Tyler -- Worker Hurt In Nasty Fall From Aerosmith Frontman's House

A construction worker was badly injured after falling from Steven Tyler's house this morning, plunging several stories ... before getting airlifted to a hospital -- and TMZ has video of the rescue.

A neighbor tells us ... the worker plunged from scaffolding on the back of the 4-5 story building, which is built into the side of a steep hill -- making the roof even further from the ground below.

When he hit the ground, we're told the man couldn't move and was screaming in agony.

Steven wasn't home when it happened around 9:30 AM -- according to his rep, the singer's been traveling overseas.

We're told the large-scale construction project on his house has been going on for several months, and Steven regularly checks up on its progress.

So far, the exact condition of the worker -- around 30 years old -- is unclear ... but we're told he's in bad shape.