Ryan air is OK (GBP 23 Milan to Prestwick - who can argue with thast?) as long as you dont want to eat or drink anything on board and dont mind not being able to reserve a seat - generally not a problem if you are travelling on your own. The cardinal rule should be to avoid Heathrow if you can - we sat waiting for a parking space at T4 for 50 mins last Fri - (Alitalia) that would never happen with Ryanair.