You have received a fraudulant e-mail. Go back to the original ebay listing and click on the "ask the seller a question" button and send an e-mail that way. That should go to the real seller. Then explain your situation and see if he is willing to allow you to pay cash and pick up the plane in person. (but be careful... you never can trust that every seller is on the up and up... check his feedback)

What is happening to you is this:
Someone obviously went on there and saw that you won the auction. (they probably were able to look at the bidders list to do this to the other people too) They clicked on your user name and sent you an e-mail making it look like a real second chance offer. They would put in their paypal info so that you would send the money to the wrong account. The real seller would not know about this going on.

Try contacting the real seller using the above method and hopefully it will work out. It would also be a good idea to notify Ebay so that they can look into this.