they would be in the flying insects species.
I soppose they are birds
Not specifically. There is a Mexican Honey Wasp (Brachygastra mellifica), one of 12 species of Brachygastra, which are wasps that produce honey. The honey is harvested and eaten in Mexico and Brazil.
Chrysura pacifica
Some species of wasp are but not all.
Only a few species of wasp live a social life in northern California. You will find yellow jackets, paper wasps, and mud daubers in the area.
No. If they were, why would they have the same name?
A bee or wasp
The insect that is called a yellow jacket in the US is called a wasp in the UK, so they are the same. Having said that, there are about 75,000 known species of wasp with widely varying body forms and habits.
tracker slacker
There are several photos of underground wasp nests on the Internet. Several different species of wasp build their nests underground.
There are approximately 700 species of paper wasp that can be found world-wide. Most, however, can be found in the western hemisphere in the sub-tropics.
The hornet referenced above, Vespa mandarinia, is the world's largest species of social wasp. The largest species of spider wasp (genus Pepsis) from South America and the giant scoliid wasp of Indonesia, Megascolia procer, are much bigger. Pepsis wasps have the largest wingspan at over 12 cm, of any wasp; Megascolia, because of its robustness, probably has the largest body. Several Pepsis species can exceed 6 cm in body length; The broader Megascolia can reach 6 cm in body length and over 10 cm in wingspan.