Most of this UAV stuff will be in the future (next few years) as I get used to the Axon and get funds for the $$$ gps and other gadgets. What I was planning was for hands off hover (i'm focusing on helicopters, if i wanted a plane autopilot i would just spend $400 on a picopilot), I could use a laser rangefinder. While in foward flight, the terrain could change a lot, so a barometric sensor (or something of that sorts) could be mounted above the rotors and out of turbulence.
Landing will probably consist of getting it into a hover over the landing position (through gps), and then manually land it. Of course all of this will once again be a long time from now, the basic UAV helicopter needs a 3 axis gyro and accelerometer along with the altitude holder and that might take a while to get funds.
I'm sure with the plane you can just get it to circle over you, and then manually take over for a landing. Auto landing is really hard, as you have to hit the right spot in the runway so that you dont run out of space, or you land before the runway. Also crosswinds are easy to overcome in manual landings, but an auto landing with crosswind is difficult (usually needing some windspeed indicator to determine which way the wind is blowing)