Advair and flovent - what's the difference between the two discs?

Depends. Advair has two medications in it, an inhaled steroid (ICS) and a long acting bronchodilator (LABA). The LABA acts for about 12 hrs, and the ICS has a longer, cumulative effect. In order to have the medication help you, you need to take the Advair every 12 hrs. The Flovent (an ICS) can be taken every 12 to 24 hours, depending on your asthma severity and the dose you are given.
Flovent is in advair. Advair contains fluticasone, a steroid, and salmeterol, a long acting bronchodialtor. Flovent contains just fluticasone. Advair is generally reserved for people with more difficult to treat asthma.