I fly to Valencia 3 to 4 times a year. And you have lots of options. My father usually flies to Alicante and takes the bus at the airport. It is really handy and cheap. We also find that hiring a car in Alicante is cheaper than in Valencia and you have the A7 motorway (again just by the airport) that brings you straight to Valencia (it takes about 1 hour and there are 2 stops in Valencia). From Barcelona, you can fly with Vueling.com for €10 each way or Spanair for €25 each way (per adult). Are you staying in the city itself?