My first Airstream was a 2005 25'SS Safari and I pulled it with a 2005 Ford Expedition (5.4L V8). The Expedition did a great job towing the 25 footer. No problems; it was like it wasn't back there. Both the trailer and the TV were wrecked in 2008; the Airstream was totalled, the Expedition was repaired. I then purchased a 2007 27FB Safari SE and towed it with the Expedition. I don't know wether the increase in weight/length, or the Expedition being formerly wrecked had anything to do with it, but the Expedition did not perform as well towing the 27'; it seemed underpowered and unstable. I traded the Expedition in for an F350 Dually; needless to say, no probs towing now.
Bottom line: An Expedition is a great tow vehicle for a 25' or below Airstream.