If changes aren't made, that near-miss becomes a mid-air collision,” one aviation safety expert said. “Unfortunately, that's what we had last night.”

Questions remain over the mid-air collision between a jet, which was carrying 64 people, including the crew, and a military helicopter carrying three soldiers

A regional jet flown for American Airlines Group Inc. collided in a deadly midair crash with a military helicopter as it flew into Ronald Reagan Washington National Airport, prompting a search and rescue operation for any survivors in the Potomac River.