Regarding Fringe, I don't think those should be considered plot holes, actually, because such details are hardly relevant to the overall story. I'm not saying details AREN'T important, I'm just saying it could be much, much worse. 
And about the New York - Boston thing, I THINK they fly most of the time. I'm not sure…

Yes, Sengupta is right! :)

Maybe we'll see in tomorrow's Astrid centric episode. We haven't had much on the background of either Astrid to be able to determine anything.