When purchasing an aircraft a bill of sale is created to show transfer of ownership from the seller to the buyer. Bills of sale include what the seller was paid in exchange for the plane. But apparently bills of sale for aircraft are commonly done differently.
The first item to fill in is the price of the aircraft, where it says "For and in consideration of
$___." To preserve the confidentiality of the transaction, the FAA will accept the phrase “$1 & OVC” (Other Valuable Considerations) in this spot, and most Bills of Sale are filled out in this fashion. source
At first I thought maybe it was some way to get out of sales or use tax, but the FAA would certainly not approve tax evasion. The state will calculate taxes either from the lien amount or the usual market value. This would definitely not pass muster for the sale of a car or a house. The only time the state treasurer ever had me put $1 was when I was giving a car to a family member.
Obviously the price is being withheld for some reason, but I can't really figure out what that reason is. The price is easily found with a records search. The only person this hides the sale price from is the FAA. And since the FAA approves that wording they obviously don't care. Why do people not want the FAA to know how much they paid for their plane?