I've had Airstreams for twenty years, since 1987 until I bought my Bigfoot 25RQ. Frankly, I cringed at every thunderstorm, and the insurance on the last Airstream I had, a 1994 34' tri-axle was twice what I pay for my '06 Bigfoot.
Now, that said, in 1993 the WBCCI International Rally
was held in Bismarck N.D. One night during the International that year, a terrible thunderstorm hit with golf ball to soft ball size hail. Those Airstreams became known as "Bismarck Units" and were easily identified because they looked like silver golf balls. Some of them were totalled, and some repaired. Many folks took the insurance settlement and continued to use their units. As the years passed, and the heat/cold summer/winter cycles continued, after a couple of years most of those dents returned to their original form. Occasionally you can still see hail dents, but after a couple of years most of them heal themselves, so it's not as catastrophic as it might seem. I think the later model Airstreams are more susceptible to damage as the aluminum alloy is so much more thin than it was even in the '70s.