Spokeswoman Liz Landau says Flight 749 from Madrid was heading to Charlotte, N.C., Saturday morning with 192 passengers and a crew of nine, but had to land in Boston shortly after 11 a.m.
Landau says the smoke had dissipated by the time the plane landed, and no passengers complained of any problems. She says she doesn't know whether the flight attendants have been released from the hospital.
The plane has been taken out of service, and Landau says mechanics are trying to determine what caused the smoke.
She says the passengers were put on another plane to Charlotte.
