Travel in Europe ... train vs. plane?

I am going to Angers, France for 4 months and I have several weekends that are 3.5 or 4 days long. Is it better to travel via planes or via trains? I mean in regards to cost vs time. I will have a muli-entrance visa so that should not be an issue. Also I am looking specifically at Ireland, Spain, Portugal, S. France, and Italy. Thanks!

train is cheaper but flying is faster

good airlines for discounts are ryanair, wizzair

for countries like spain, portugal, France and Italy I would recommend a train. it is cheaper.
http://www.tgv.com/
http://www.nshispeed.nl/en/rondreistickets/discover-europe-by-using-interrail



for Ireland it is faster to go by plane.
easyjet, ryanair, skyeurop. are cheap.