You can't just say, lean back and look for your landing, because that is why most people actually get hurt attempting backflips. You should try this on your trampoline first, then once you have it down pat, try it off a small kicker:
The key to a backflip is in the hips, not the upper body. You are supposed to rotate around your hips, so, using physics, if you set a flip at the fulcrum (sp), rather than at the extremities, you will not have to try as hard. Put your hands on your hips, just like a girl does: this is where you set your flip. Pick a point that is ahead and up from you (like a high up tree branch) and try to throw your hips at that branch. This will cause your back to arch and your feet to swing out in front of you. If done right, you will naturally, without any effort, be looking for your langing as your head swings around. If you feel like you need to throw your head to see your landing, then you are doing it wrong. Set rightly, you will not travel backwards during your flip. Infact, the better you get at "setting" the flip (the initial thrust of the hips), the more you will travel forward from your starting point and the easier it will be to get around. Once you master that, you can try and tuck up to grab a mute or safety, or throw it back and to the side for a rodeo/dspin. Remember, the key to a successful backflip on the trampoline is setting the hips.
On the snow it is pretty much the same thing. You do not need a lot of air to do it. Hit the jump a few times to get a sense of how long you have. Then go into the jump a little bit bending forward at the waist. WHen you hit the jump, POP FIRST. If you dont pop and just throw your head, you can hit it on the jump, which is really embarresing, trust me! After you have poped, throw your hips just like you did on the trampoline. It is literally the exact same feeling, only now you are traveling forward.
Hope that helps!