If I were you, I'd stick with sub 150 - 200 ish iem. My experience with portable on board of a plane is nothing short of nightmare. Left my sennheiser cx (forgot the series) and lost it, burned my tf10 on airplane headphone out, slept on my jh13 and broke the connector.
Now after all the fiasco, I've come to conclusion that the best place to enjoy ultimate SQ is frm the comfort of my home. As long as I can hv decent SQ, not bulky, blocks majority of the plane noise and can sleep with the iem on while I travel, I'm happy. Not going to chase fr the last 10-15 % of the perfection.