I take lunesta and klonopin at night some times
benzos are safe in relatively high dosages. So you should be ok, but if you mix the too you may find your self far more sedated than planned, not really a bad thing on a plane ride but for an everyday situation: set an alarm next to the light switch so when you wake up, stumble out of bed feeling very groggy you can immediately turn on a bright light when you turn off the alarm. (this should quell your urge to go right back to sleep after turning off your alarm)
[speaking form experience here].
as stated above, if you have normal benzo tolerance then one lunesta should suffice, or maybe one full strength (3mg). you shouldn't need to take more than that
but 3mg eszopiclone + maybe .5mg or 1mg klonopin, and you should be sound asleep for the plane ride.