As reported on earlier this month, Ric Flair is indeed under contract with WWE signing a new deal with the company recently. Any of his appearances and business deals now have to be cleared by WWE first. While Flair is allowed to take bookings outside of WWE, they have a clause in his deal that if they need him for anything then the original booking he had is off immediately. Booking Flair reportedly costs in the $10,000 or so range in addition to money spent on advertising, transportation and hotels.
Ric Flair confirmed to be under new WWE deal, booking note
