BOISE, Idaho — A United Airlines captain suffered an apparent heart attack while piloting a plane from Houston to Seattle and passengers stepped in to help with a doctor performing CPR and an off-duty pilot assisting in the emergency landing in Idaho.

The captain was still alive when he arrived at Saint Alphonsus Regional Medical Center but died overnight while undergoing treatment, spokeswoman Jennifer Krajnik said Friday. A Boise airport spokeswoman said Thursday that the man suffered an apparent heart attack. The cause of death has not been announced.

The news lit up social media in the early morning hours Friday, with dozens of tweets sent out about the pilot's death.