Hello, I'm from England but my job frequently takes me to Los Angeles. Can anyone recommend any fishing opportunities in the LA area?

I'd also like to stretch a business trip with a weekend's fly fishing elsewhere in the US. The problem's access, by the time I've got to the water it's time to pack up and go. Anyone any suggestions for great fly fishing that's reasonably accessible from a major airport? I realise international hubs and trout don't usually mix, but any thoughts would be greatly appreciated!