Tour operators come and go, but the basic comuter flight remains.
Walk or take a taxi to the ruin, pay your fee and the gate. I don't think it's walking distance because I've taken a taxi from Valladolid to Chichen Itza and passed the airport sign. If that's the same airport, it' s not walking distance. It didn't seem like such a big savings when I could have someone else make all of the arrangements for me. It's my guess that the package tour is worth the price.