GROUNDED: ASHLEY OLSEN Smoke-Filled Cockpit Grounds Flight at DFW

Ashley Olsen was on board an American Airlines flight when smoke forced pilots to abort take-off this morning ... TMZ has learned. Sources on board AA flight 2421 tell us the plane was departing from Dallas when something went wrong with an engine shortly after pulling away from the gate. According to fire officials at DFW ... the cockpit filled with smoke, and the pilots quickly returned to the terminal. Our sources say Ashley was among the roughly 200 passengers who got off the plane safely. UPDATE: An American Airlines rep says the flight returned to the gate due to an electrical odor in the cockpit ... and a new Boeing 767 was brought in to take all 211 passengers to LAX. The rep says the flight was delayed less than 2 hours.