Boeing 737 Windshield Crack: Weather Balloon Suspected After United Flight Diverted

A Boeing 737 windshield crack mid-flight forced a United Airlines flight to divert last week, and investigators are now looking into whether a weather balloon may have been the cause. The incident occurred on October 16, 2025, when United Flight 1093 from Denver to Los Angeles diverted to Salt Lake City after pilots noticed a crack in one of the windshield’s layers.

The National Transportation Safety Board (NTSB) confirmed that the cracked windscreen is now under examination at its laboratory. Officials said the multilayer windshield design kept the aircraft operational, ensuring the safety of the 134 passengers and six crew members onboard. The plane landed without incident, and another aircraft completed the journey to Los Angeles.

Weather Balloon Collision May Have Caused Boeing 737 Windshield Crack

Investigators are focusing on whether an external object struck the Boeing 737’s windshield mid-flight. One leading theory is that a weather balloon may have been responsible. John Dean, CEO and co-founder of Palo Alto-based WindBorne Systems, said in a social media post that one of his company’s balloons could have been involved.

“I think this was a WindBorne balloon,” Dean stated. “We learned about UA1093 and the potential link to one of our balloons late Sunday and immediately began investigating. We submitted our preliminary findings to the NTSB and FAA early Monday and are cooperating fully.”

WindBorne Systems operates a network of lightweight, long-duration weather balloons that gather meteorological data for U.S. and international agencies. Dean added that the company has implemented new software protocols to reduce the time balloons spend at commercial flight levels, aiming to prevent similar incidents.

The NTSB will interview the flight crew and review flight data and cockpit voice recordings to determine if the aircraft collided with a foreign object. The investigation will also examine the windshield’s structure and the dynamics of any mid-air impact.

Safety Measures and Broader Aviation Implications

Although the Boeing 737’s windshield sustained a crack, the multilayer design ensured continued performance, preventing a dangerous decompression scenario. Aviation experts emphasize that modern airliner windshields are built with multiple layers of reinforced glass and plastic to withstand extreme pressure differences and minor impacts.

This incident highlights potential safety risks posed by high-altitude weather balloons. While they provide vital meteorological data, their increasing numbers near commercial flight paths raise new safety questions. Aviation regulators may consider issuing new operational guidelines or altitude restrictions for balloon operators.

United Airlines reassured passengers that safety remains its top priority. “The flight diverted out of an abundance of caution, and all passengers reached their destination safely,” the airline said in a statement.

The Boeing 737 windshield crack incident serves as a reminder of the complex interactions between aviation and atmospheric technology. As investigations continue, findings from this case could shape future airspace safety protocols and weather data collection methods.

FYI (keeping you in the loop)-

Q1: What caused the Boeing 737 windshield crack?

Investigators suspect a weather balloon collided with the aircraft mid-flight, causing one layer of the windshield to crack.

Q2: Was the United flight able to land safely?

Yes. The Boeing 737 diverted to Salt Lake City and landed safely. Passengers were transferred to another aircraft bound for Los Angeles.

Q3: Who operates the suspected weather balloon?

WindBorne Systems, a California-based company that deploys weather balloons to improve forecasting, is believed to have operated the balloon involved.

Q4: What happens next in the investigation?

The NTSB is examining the windshield, interviewing the crew, and reviewing flight data to determine the cause of the damage.

Q5: How do Boeing 737 windshields protect against damage?

They use multilayer construction, allowing the windshield to remain functional even if one layer is cracked.