Teacher3rd,
Our Airstream also developed a crack over the door. The factory service manager told me that it is a common problem. You'd think that after 40-50 years of building essentially the same trailer Airstream might have fixed this by now. I'll bet that the
1965 Volkwagons didn't have any of the recurring problems that the
1950 ones did.
I had visions of replacing the entire side of the trailer, with windows, a door, decals, and sundry expensive add-ons. The service manager suggested a patch that extended from the top of the door to the roof seam. It was a fraction of the cost I had been imagining.
The patch is obvious to anyone who looks for it, but it doesn't look bad. For the thousands of dollars saved, I think it looks great.
The factory did good work and saved me quite a bit of money.
Good luck with yours.
Loren