Air, and mouse on mars? They're both kind of electronic-based music, but there's something about their unique styles that i just really dig.
Mouse on Mars are brilliant. I can't think of many bands - even of that genre - that sound quite like MoM. Perhaps you might like Boards of Canada.
Bands similar to Mouse on Mars is a bit tricky, I'm thinking maybe Auteche or Aphex Twin. Air a bit easier, maybe check out some Death In Vegas, Morcheeba, Zero 7, Orbital, Royksopp...They may not all be exact matches but an Air fan will probably enjoy them. And there's never any harm in picking up some Brian Eno albums.
I don't know any of those bands, but electronic-based and odd...I think immediately of Thievery Corporation. If you've seen Vanilla Sky, one of their songs is in there in the scene where Tom Cruise comes into the club wearing the mask... yea..I don't know. They're a cool group even if they don't sound like anyone.
Check out Stereolab, U-Ziq, Red Snapper, Postal Service, Massive Attack, Koop, and Supreme Beings of Leisure... I think they'll fit the bill
First album by French electronic band Mellow called "Another Mellow Summer" is totally inspired by Air's Moon Safari album in fact too close for comfort sometimes. The band are also influenced by 60's orchestral psych pop along the lines of Sgt Pepper and are also influenced by Kevin Ayers and Nick Drake and these influences are much stronger on the second album "Perfect Colours" than the Air sound of the first album. Nice mix of pastoral sounds and psych pop with their electronica if you want something like Air I'd go with the first album. Someone mentioned Zero 7, great band and again very influenced by Moon Safari.