Japanese giant hornet????
Photos of huge angry, aggressive hornet. We're used to the humongous cicada killers but this is different and very human aggressive. My son captured it and as it literally was prying open a crack in the plastic jar he gave it a shot of ether from the garage killing it instantly (good thing he doesn't do anesthesia!) He put it in another jar that had cement dust in it unfortunately so the grey is dust.
This is a European Hornet. They are generally not aggressive unless provoked or defending a nest with many others. It is rare to see a nest.
He was probably just annoyed at being in a jar.
They are considered beneficial and should be conserved.
Here is our page on them: http://extension.umd.edu/hgic/european-hornets
Asian hornets are not found in Maryland.