hi there,
are you going to be flying from Barcelona to Madrid and then from Madrid to Paris? Coz that was what we did.
It was simple to just buy the air shuttle ticket for Bar-Mad at the Airport (terminal2). No problem with paying by credit cards but do shop ard among the airline offices there for the best value. We went to Air Europa first but they were about almost 8000 PTAs more than Iberia Airlines (which was the national carrier)! so we went with Iberia which was good and the staff at the counter spoke a bit better english as well..
But maybe due to June being peak tourist season, it might be better to try reserving online and you might even get it cheaper actually i think.
As for flying from Madrid to Paris, we took AIR FRANCE and we had already bought the tickets from home to save us the hassle of trying to buy them there. My advice would be to do as much as possible from home. Make full use of the internet! it was our saviour! just as this forum was!
heheh...
and just FYI, on our trip, we did Barcelona, Madrid, Paris (twice!), London, Vienna and Munich!!! and took various forms of transportation : planes, trains and automobiles (u name it,we took it!) ....
so if there's any more info you need to know..just gimme a buzz ok?
cheers!