Ohio Revised Code Section 5741.02 http://codes.ohio.gov/orc/5741.02v1 imposes a tax on “on the storage, use, or other consumption in this state of tangible personal property.” The tax rate is 5.75%.
The use tax exempts (5741.02(C)(2))“ tangible personal property or services, the acquisition of which, if made in Ohio, would be a sale not subject to the tax imposed by sections 5739.01 to 5739.31 of the Revised Code”
Since Ohio appears to have a “Casual Sale” exemption from the sales tax, ((L) "Casual sale" being defined as “a sale of an item of tangible personal property that was obtained by the person making the sale, through purchase or otherwise, for the person's own use and was previously subject to any state's taxing jurisdiction on its sale or use, and includes such items acquired for the seller's use that are sold by an auctioneer employed directly by the person for such purpose, provided the location of such sales is not the auctioneer's permanent place of business. As used in this division, "permanent place of business" includes any location where such auctioneer has conducted more than two auctions during the year.”) then it would appear that under 5741.02(C)(2) you would be exempt as long as your seller was not in the business of selling aircraft (and thereby subject to the sales tax in his state).