I, too, find it strange if, as you say, most of the shots here are right to left. Last night I was reading in a National Geographic photo tips book called "Field Guide: Secrets to Making Great Pictures" in a section about composition, and they mention that because in Western cultures people read from left to right, subjects should be placed "closer to the left side of the frame," and also you should "leave space for a moving subject to travel into...". This seems to suggest, according to the National Geographic people, airplanes "should" be shot moving from left to right. That is what they think. What I think is take what you can get! Maybe they weren't writing specifically about airliners, but rather just a general piece of advice. Anyway, as for me, I am lucky to get a good spotting position, much less be picky about whether I want to shoot a left or right-going airplane. Oh, well... I guess that is one more thing I'll have to worry about when I get to be super good!