Ah, the fever of speculation. This is an interesting report from a local paper in Ohio, which found an eyewitness to the alleged Palin plane:
According to Rich Bevis of B&B Aero, the fixed-based operator at Hook Field, the jet, a Gulfstream IV which has the flight range to fly from Alaska to Europe, landed at about 10:15 p.m. Thursday, Aug. 28.
Bevis said the woman “was a real close match to Palin” and added that the flight crew that’s based in the Seattle area was told to fly to Anchorage to pick up their party and fly to Middletown.
Bevis said the jet had a woman, two teenagers and two men on board and that a couple of white vans met the plane, gathered their gear and took the party to an undisclosed location
(OxfordPress)
And yes, Palin has two teenage daughters (Bristol & Willow).