purchase a B.A.L. jack specific for Airstream. I've seen B.A.L. jacks on the company's website
, eBay, Amazon, CW and at SOB RV dealers -- don't get these! The shafts on standard B.A.L. jacks are too short to come out from under an Airstream's curved belly. Airstream-specific B.A.L. jacks have longer shafts to make up for the mounting position on the fore and aft frame member. You just about have to go with an Airstream dealer.
Here are other popular sources for Airstream parts & info -- very
knowledgeable dealers: OutofDoorsMart
or OASIS R.V. CENTER, INC. - Home
. Their parts departments are great over the phone but you'll want to understand shipping costs for such heavy items.