A very good evening , mothers asked me tonight is it possible to fly to lisbon from faro for the day ? she would like to visit but not for the whole week ,has anyone ever done this if so is it easy and what kind of price are we talking? thanks in advance

TAP do regular flights but to be honest, by the time you have got to the airport and all the mucking around that entails, you are probably better off taking the train. I've not done it yet but I've heard it's fast, cheap and comfortable.

Here's a previous thread on the subject.

Aero-Algarve or Aero VIP can offer an air taxi service for the day from Portimao airport (nearer to Alvor) to Cascais and back for around €150 per person.

Flight time around 50 minutes and 20 - 30 minutes to Lisbon centre, giving up to 10 hours there.

If time is more important than price then this is the way to do it. If the reverse, then train at about €30 taking 3 hours from Silves and 10 minutes to centre is the best option, but giving only 6 hours there.