* A work of art that's appraised at $10,000, for example, but that's priced for sale at $5000, is not necessarily a bargain. As stated above, a retail or insurance appraisal can be many times the fair market value of a work of art. Always determine fair market value first, no matter how big a bargain the seller makes you think you're getting.
In general the aircraft must be at least 500 feet away from any person, vessel, vehicle, or structure. In congested areas the aircraft must stay 1000 feet above the highest obstacle within a 2000 foot radius of the aircraft. There are special rules for helicopters that allow them to fly closer than these general limits.
No person may operate a civil aircraft of U.S. registry 1  -. (1) At cabin pressure altitudes above 12,500 feet (MSL) up to and including 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen for that part of the flight at those altitudes that is of more than 30 minutes duration;