Delta Flight 511, a nonstop from Cincinnati, was over the Pacific Ocean when the passenger had "a complete meltdown freakout," said a fellow passenger who called The Associated Press from the tarmac at San Francisco International Airport.
The flight was turned around after the woman hit a pilot who had left the cockpit to quell the disturbance, said Elizabeth Oglesby of Atlanta.
"She appeared to be out of her mind. Upset. Belligerent," Oglesby said. "He threatened to handcuff her if she didn't calm down. At that point she hit him in the chest."
The woman was given oxygen and was taken to the hospital by ambulance after the plane landed.
Officials with the Transportation Security Administration and Federal Aviation Administration did not immediately release the name of the passenger and it was not clear if she would face criminal charges. It's a federal crime to smoke on a commercial flight.
Delta spokeswoman Chris Kelly said the Boeing 767 landed safely at about 1 p.m. and resumed its flight about an hour later.
"I wish I was on the beach right now," Oglesby said before the flight resumed. "I think Delta did the right thing. You don't hit a pilot in an airplane."