In the US, the National Transportation Safety Board is investigating the midair collision in late October between a United Airlines flight and a lightweight weather balloon over Moab, Utah that left the pilot injured and prompted an emergency landing in Salt Lake City.

According to a report on the KOMO TV News website, the Boeing 737 was flying at 36,002 feet when it crossed paths with a high-altitude balloon from WindBorne Systems of Palo Alto, California. News reports said that the lightweight global sounding balloon was launched a day earlier from Spokane, Washington. Global sounding balloons use radiosondes to transmit atmospheric conditions and other data gathered during their flights.

A statement on the WindBorne company website said that the incident was the only midair impact in the company's record of more than 4,000 launches. Media reports said the captain's right arm suffered minor cuts and some of the flight crew members were hit by glass from the first officer's shattered windshield.

No cabin pressure was lost and the plane was landed safely without further incident.