I have been away for the festive season and the only headphones I had was my Sony XM2 for the flights which I sold since then. I just couldn't get used to that hazy and mid-bassy sound.
Since then I am looking for better portable options, will test a Campfire Comet with EarStudio ES100 soon. I don't really want to spend more than this since I only fly 4-5 times a year. If I don't like the Comet my next option is the Ety ER3XR or instead of the ES100 the Spectra X DAC. The ES100 is surprisingly good for the price so far, but haven't tried with the Comet yet.
My next flight is only in a couple of months, so I have got some play time.
Why I am bringing this up is the EQ talk and the infinite love towards Loki in this thread. I had a longer post a few weeks ago about refinement of taste and how we are able to learn and appreciate new subtleties in taste, think of red wine or whiskey or cheeses. My argument was that our audio taste can get more refined by time as well, and EQ most of the time is like ketchup that we are used to and refuse to get rid of.
I still think EQ-ing is a slippery slope if you want your taste to keep improving. However I was also considering buying the Loki to add some extra bass and to ease out treble crispness at times. I am still not sure however, if that's the right way instead of buying a more refined, better-balanced amp.
What my 2 weeks away taught me with the Sony XM2 is that our ears/brain need a much longer adjustment period to new sound and to another sound signature than we think. 2-3 days at least. Coming back from holiday my ears/brain had to readjust to my system with the 2C. Initially it felt thin and bass-light after the XM2, although air and space and refinement was immediately better. (Makes me question any A/B headphone testing.)
Don't rush with EQ guys, don't rush with Loki. Let your ears learn what you have got. After you know what you've got, you will know how you want to tweak that sound if you want to tweak anything at all. Wait with adjustments is my 2 cents for the week.