Most commercial aircraft are struck by lightning at least once a year. Usually the aircraft itself is responsible for triggering the lightning, by flying through a heavily charged region of cloud. Passengers and crew might see the flash and hear a loud noise, but normally the lightning travels over the conductive exterior of the plane and causes no immediate damage. However, the plane has to be taken out of service after every lightning strike for inspection, often causing delays and cancellations.
Now a study published in the Journal of Geophysical Research: Atmospheres has found a way that aircraft could make themselves less vulnerable to lightning. Using a model aircraft in the lab, the researchers experimented with different levels of charge on the exterior of the plane and monitored what happened when they flew it into electrically charged air. Ordinarily aircraft are designed to be electrically neutral, to avoid build-up of static charge, but to their surprise the researchers found that neutral planes are more prone to lightning strikes. Instead they found that the charged version of the model plane was least likely to trigger lightning. Exactly how this might translate to the real world remains to be seen, but it has potential to save time and money.