Did you go for the SE530PTH?

It is worth paying the extra to get the Push To Hear Module as if travelling you have to keep popping the IEMs out to talk to crew, hear announcements etc whereas the PTH module lets you flick a switch and hear external noise through your earphones.

You can also buy it on its own if needed. I have these headphones and they really are superb.

For those not wanting to spend so much then the main thing is to get good isolation. Higher end IEMs come with a range of tips such as silicon flanges, foam etc. If you want to just improve your existing IEMs then check out Comply and pick up some of their foam tips for your earphones, if supported.