I am going to replace the pen flare with a 15 min road flare. If using it to signal I will have 15 minutes to wave it around like a mad man in the hopes someone will see it. At night someone in a plane or chopper or on the ground looking for you should look in your direction hopefully at least once in the span of 15 minutes.
Just be careful about waving flares around. Some of them like to drop red-hot, plasma-of-death, burning liquid all over the place.
Although the resulting screaming and cussing that happens after you get some of that stuff on you might get the rescuers’ attention, too.
Excellent documentary post of using the pen flares, as well!