Hopefully injections/needles are allowed on flights at this time? I haven't checked on that for a while, but this is where I've found the nasal spray version of the triptan to be a nice reassuring pocket pal to have on a flight (if you have any of those laying about). I've been a straight up syringe-with-q-tip-used-as-the-plunger guy for injections for awhile though, and that pretty much screams out for excusing oneself to the lavatory, whereas I could see an auto-injector being deployed more discretely whilst still strapped into seat.
If needles are allowed onboard, one more thought: Have it on your person at all times, not stored in the overhead, as that ain't gonna be accessible during times like take off/landing.