difference between vfr and ifr
VFR or Visual Flight Rules means you generally have good visibility and are in a certain range of altitudes. You basically fly using what you see (and of course navaids and charts). IFR or Instrument Flight Rules are used at certain altitudes, with certain types of aircraft and under certain kinds of visibility. Under IFR, you fly by using navaids, charts and instruments. Oftentimes you'll have zero visibility but IFR lets you fly in these assuming you're IFR certified.