American Airlines CEO Robert Isom expressed his "deep sorrow" after a passenger plane and a military helicopter collided on Wednesday night (29 January).
A regional jet carrying 64 people collided mid-air with an Army Black Hawk helicopter in Washington DC.
All 67 people on board both aircraft are feared dead, Kansas senator Roger Marshall said.
"Our efforts now are focused entirely on the needs of our passengers, crew members, partners, first responders, along with their families and loved ones," Mr Isom said in a video message.
