Nevado: Thanks for opening up the old "surcharge" wound I had almost forgotten about that. The shuttle bus from Barajas to the Hotel Madrid did NOT charge me, but we couldn't take it from the hotel to the airport on the way out since we had to leave at 5:30 a.m.

We got fleeced since it was a día feriado and all the taxis were in use [seriously...] in the a.m. from the night's partying. Our friends at Hotel Madrid called a couple of buddies to pick us up...at 30 euros per.

That is good information to have on the taxi surcharge though. You might consider putting a few extra bungee cords or some rope in your bike box. Odds are that your taxista won't have nearly enough to do the job right.