lajolla

We will be arriving in Madrid in mid. October for a 3 week trip to northern spain & dordogne area of France. We will.be renting a car. We want to limit number of hotel moves. Is it easier to just fly on to Bilbao following landing in madrid or driving to Bilbao from there? our first destination is Bilbao. We will be spending a week in Madrid at the end.

Southam

The flight from Madrid to Bilbao takes one hour, with at least three airlines on the route. This site will give you some idea of times and prices http://www.whichbudget.com/routes/MA...to-bilbao.html
Much more time can be eaten up connecting from your arrival flight. Of the three services I found, Iberia would be the most likely to have a luggage arrangement with your initial airline allowing you to check your bags through, rather than collecting them and checking back in with another airline.
I cannot think of any other reason to favour Iberia.
Michelin calculates the shortest drive to be 385 km and about 5 1/2 hours www.viamichelin.com
One small bonus to flying: The highway from the airport into the city offers a unique perspective on the Guggenheim Museum, driving almost through one of its roofs.
Give Bilbao a chance to charm you; There's more to this old industrial city than the Guggenheim, including a good beaux-arts museum and pretty tasty dining