I use a diffuser in very shallow water on the edge of the pond for my 1/10th acre trout pond. My pond drops off very rapidly so the diffuser is actually sitting right on the edge of the pond. I also remove snow off the ice. I use a small 1/20th hp. compressor for this. It's this one the DC 22 on this page:

http://www.stoneycreekequip.com/form/air_compressor.htm

Optimally diffuser and airline stay permanently in the pond with only a change over from the summer large compressor and it's airline and diffuser to this smaller compressor, airline and diffuser in winter. I hate moving airlines etc!

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.