Welcome to the forums. I see by your profile that you are currently looking. Does your question about dents concern an Airstream you are considering purchasing?
What you will find is that there are two types of dents. The first is one that is just pushed in but not on an end cap. If this dent does not also have a crease it most likely can be taken out with a suction cup. The second is the creased dent. These pose more problems in that once the aluminum has been stretched it can not be shrunk back into its original shape. The location of the dent also has a lot to do with it repair-ability. Some dents you can get at by removing an interior panel. I have one on the back corner of Chummy and I would need to remove the shower and sink assembly in order to get at it from the inside. I simply gave it a name for the foolish way it got there.
There are members who have done wonderful things to thier dents and you can find these threads by using the search feature.
Good luck to you and I hope you do find the Airstream which is perfect for you.
1994 30' Excella 1000, Chummy III- Ford Excursion- 7.3 Turbo-diesel