Thank you, when I left last time I did this , I was hoping there might be an alternative, I found Madrid airport a nightmare! I was traveling with a Norwegian airline that was quite a distance from where bus from astorga dropped me at one part of airport, got home eventually!!I usually fly to Madrid from Bristol with Easy jet. There is some trains that go through Astorga from Madrid ( I think), and there is buses galore that go through Astorga from Madrid, (Alsa) I caught one to Ponferrada and it stopped of in Astorga on the way.
Easyjet, Renfe , Alsa can all be very cheap or expensive, depending how close to the Journeys you book, the season you travel and day you travel, the only way to find out for sure is go on the websites and match different days or weeks up.